feat: add eligibility check flow with form, OTP, and success steps

- Implemented FormStep component for user input (name, email, address).
- Created OtpStep component for OTP verification.
- Developed SuccessStep component to display success messages based on account creation.
- Introduced eligibility-check.store for managing state throughout the eligibility check process.
- Added commitlint configuration for standardized commit messages.
- Configured knip for workspace management and project structure.

.husky/commit-msg

@@ -0,0 +1 @@
+pnpm commitlint --edit $1

CLAUDE.md

@@ -6,9 +6,14 @@ Instructions for Claude Code working in this repository.
 
 ## Agent Behavior
 
+**Always use `pnpm`** — never use `npm`, `yarn`, or `npx`:
+
+- Use `pnpm exec` to run local binaries (e.g., `pnpm exec prisma migrate status`)
+- Use `pnpm dlx` for one-off package execution (e.g., `pnpm dlx ts-prune`)
+
 **Do NOT** run long-running processes without explicit permission:
 
-- `pnpm dev`, `pnpm dev:start`, `npm start`, `npm run dev`
+- `pnpm dev`, `pnpm dev:start`, or any dev server commands
 - Any command that starts servers, watchers, or blocking processes
 
 **Always ask first** before:

apps/bff/package.json

@@ -54,6 +54,7 @@
     "nestjs-zod": "^5.0.1",
     "p-queue": "^9.0.1",
     "pg": "^8.16.3",
+    "pino-http": "^11.0.0",
     "prisma": "^7.1.0",
     "rate-limiter-flexible": "^9.0.0",
     "reflect-metadata": "^0.2.2",

apps/bff/src/app.module.ts

@@ -1,6 +1,5 @@
 import { Module } from "@nestjs/common";
-import { APP_INTERCEPTOR, APP_PIPE } from "@nestjs/core";
+import { APP_INTERCEPTOR, APP_PIPE, RouterModule } from "@nestjs/core";
-import { RouterModule } from "@nestjs/core";
 import { ConfigModule } from "@nestjs/config";
 import { ScheduleModule } from "@nestjs/schedule";
 import { ZodSerializerInterceptor, ZodValidationPipe } from "nestjs-zod";

apps/bff/src/app/bootstrap.ts

@@ -7,6 +7,10 @@ import helmet from "helmet";
 import cookieParser from "cookie-parser";
 import type { CookieOptions, Response, NextFunction, Request } from "express";
 
+import { UnifiedExceptionFilter } from "../core/http/exception.filter.js";
+
+import { AppModule } from "../app.module.js";
+
 /* eslint-disable @typescript-eslint/no-namespace */
 declare global {
   namespace Express {
@@ -15,11 +19,6 @@ declare global {
     }
   }
 }
-/* eslint-enable @typescript-eslint/no-namespace */
-
-import { UnifiedExceptionFilter } from "../core/http/exception.filter.js";
-
-import { AppModule } from "../app.module.js";
 
 export async function bootstrap(): Promise<INestApplication> {
   const app = await NestFactory.create<NestExpressApplication>(AppModule, {

apps/bff/src/core/config/app.config.ts

@@ -2,7 +2,7 @@ import { resolve } from "node:path";
 import type { ConfigModuleOptions } from "@nestjs/config";
 import { validate } from "./env.validation.js";
 
-const nodeEnv = process.env.NODE_ENV || "development";
+const nodeEnv = process.env["NODE_ENV"] || "development";
 
 // pnpm sets cwd to the package directory (apps/bff) when running scripts
 const bffRoot = process.cwd();

apps/bff/src/core/config/auth-dev.config.ts

@@ -12,17 +12,17 @@ export interface DevAuthConfig {
 }
 
 export const createDevAuthConfig = (): DevAuthConfig => {
-  const isDevelopment = process.env.NODE_ENV !== "production";
+  const isDevelopment = process.env["NODE_ENV"] !== "production";
 
   return {
     // Disable CSRF protection in development for easier testing
-    disableCsrf: isDevelopment && process.env.DISABLE_CSRF === "true",
+    disableCsrf: isDevelopment && process.env["DISABLE_CSRF"] === "true",
 
     // Disable rate limiting in development
-    disableRateLimit: isDevelopment && process.env.DISABLE_RATE_LIMIT === "true",
+    disableRateLimit: isDevelopment && process.env["DISABLE_RATE_LIMIT"] === "true",
 
     // Disable account locking in development
-    disableAccountLocking: isDevelopment && process.env.DISABLE_ACCOUNT_LOCKING === "true",
+    disableAccountLocking: isDevelopment && process.env["DISABLE_ACCOUNT_LOCKING"] === "true",
 
     // Enable debug logs in development
     enableDebugLogs: isDevelopment,

apps/bff/src/core/http/exception.filter.ts

@@ -47,11 +47,11 @@ function mapHttpStatusToErrorCode(status?: number): ErrorCodeType {
  */
 interface ErrorContext {
   requestId: string;
-  userId?: string;
+  userId?: string | undefined;
   method: string;
   path: string;
-  userAgent?: string;
+  userAgent?: string | undefined;
-  ip?: string;
+  ip?: string | undefined;
 }
 
 /**
@@ -123,7 +123,7 @@ export class UnifiedExceptionFilter implements ExceptionFilter {
    */
   private extractExceptionDetails(exception: HttpException): {
     message: string;
-    code?: ErrorCodeType;
+    code?: ErrorCodeType | undefined;
   } {
     const response = exception.getResponse();
 
@@ -136,19 +136,21 @@ export class UnifiedExceptionFilter implements ExceptionFilter {
       const code = this.extractExplicitCode(responseObj);
 
       // Handle NestJS validation errors (array of messages)
-      if (Array.isArray(responseObj.message)) {
+      const messageField = responseObj["message"];
-        const firstMessage = responseObj.message.find((m): m is string => typeof m === "string");
+      if (Array.isArray(messageField)) {
+        const firstMessage = messageField.find((m): m is string => typeof m === "string");
         if (firstMessage) return { message: firstMessage, code };
       }
 
       // Handle standard message field
-      if (typeof responseObj.message === "string") {
+      if (typeof messageField === "string") {
-        return { message: responseObj.message, code };
+        return { message: messageField, code };
       }
 
       // Handle error field
-      if (typeof responseObj.error === "string") {
+      const errorField = responseObj["error"];
-        return { message: responseObj.error, code };
+      if (typeof errorField === "string") {
+        return { message: errorField, code };
       }
 
       return { message: exception.message, code };
@@ -162,16 +164,18 @@ export class UnifiedExceptionFilter implements ExceptionFilter {
    */
   private extractExplicitCode(responseObj: Record<string, unknown>): ErrorCodeType | undefined {
     // 1) Preferred: { code: "AUTH_003" }
-    if (typeof responseObj.code === "string" && this.isKnownErrorCode(responseObj.code)) {
+    const codeField = responseObj["code"];
-      return responseObj.code as ErrorCodeType;
+    if (typeof codeField === "string" && this.isKnownErrorCode(codeField)) {
+      return codeField as ErrorCodeType;
     }
 
     // 2) Standard API error format: { error: { code: "AUTH_003" } }
-    const maybeError = responseObj.error;
+    const maybeError = responseObj["error"];
     if (maybeError && typeof maybeError === "object") {
       const errorObj = maybeError as Record<string, unknown>;
-      if (typeof errorObj.code === "string" && this.isKnownErrorCode(errorObj.code)) {
+      const errorCode = errorObj["code"];
-        return errorObj.code as ErrorCodeType;
+      if (typeof errorCode === "string" && this.isKnownErrorCode(errorCode)) {
+        return errorCode as ErrorCodeType;
       }
     }
 
@@ -209,7 +213,7 @@ export class UnifiedExceptionFilter implements ExceptionFilter {
       .replace(/secret[=:]\s*[^\s]+/gi, "secret=[HIDDEN]")
       .replace(/token[=:]\s*[^\s]+/gi, "token=[HIDDEN]")
       .replace(/key[=:]\s*[^\s]+/gi, "key=[HIDDEN]")
-      .substring(0, 200); // Limit length
+      .slice(0, 200); // Limit length
   }
 
   /**

apps/bff/src/core/http/request-context.util.ts

@@ -1,8 +1,8 @@
 export interface RequestContextLike {
-  headers?: Record<string, string | string[] | undefined>;
+  headers?: Record<string, string | string[] | undefined> | undefined;
-  ip?: string;
+  ip?: string | undefined;
-  connection?: { remoteAddress?: string };
+  connection?: { remoteAddress?: string | undefined } | undefined;
-  socket?: { remoteAddress?: string };
+  socket?: { remoteAddress?: string | undefined } | undefined;
 }
 
 export function extractClientIp(request?: RequestContextLike): string {

apps/bff/src/core/logging/logging.module.ts

@@ -1,16 +1,14 @@
 import { Global, Module } from "@nestjs/common";
 import { LoggerModule } from "nestjs-pino";
+import type { Options as PinoHttpOptions } from "pino-http";
 
 const prettyLogsEnabled =
-  process.env.PRETTY_LOGS === "true" || process.env.NODE_ENV !== "production";
+  process.env["PRETTY_LOGS"] === "true" || process.env["NODE_ENV"] !== "production";
 
-@Global()
+// Build pinoHttp config - extracted to avoid type issues with exactOptionalPropertyTypes
-@Module({
+const pinoHttpConfig: PinoHttpOptions = {
-  imports: [
+  level: process.env["LOG_LEVEL"] || "info",
-    LoggerModule.forRoot({
+  name: process.env["APP_NAME"] || "customer-portal-bff",
-      pinoHttp: {
-        level: process.env.LOG_LEVEL || "info",
-        name: process.env.APP_NAME || "customer-portal-bff",
   /**
    * Reduce noise from pino-http auto logging:
    * - successful requests => debug (hidden when LOG_LEVEL=info)
@@ -40,7 +38,7 @@ const prettyLogsEnabled =
     req: (req: { method?: string; url?: string; headers?: Record<string, unknown> }) => ({
       method: req.method,
       url: req.url,
-            ...(process.env.NODE_ENV === "development" && {
+      ...(process.env["NODE_ENV"] === "development" && {
         headers: req.headers,
       }),
     }),
@@ -48,18 +46,6 @@ const prettyLogsEnabled =
       statusCode: res.statusCode,
     }),
   },
-        transport: prettyLogsEnabled
-          ? {
-              target: "pino-pretty",
-              options: {
-                colorize: true,
-                translateTime: false,
-                singleLine: true,
-                // keep level for coloring but drop other noisy metadata
-                ignore: "pid,req,res,context,name,time",
-              },
-            }
-          : undefined,
   redact: {
     paths: [
       "req.headers.authorization",
@@ -78,9 +64,25 @@ const prettyLogsEnabled =
     level: (label: string) => ({ level: label }),
     bindings: () => ({}),
   },
+};
+
+// Add transport only in development to avoid type issues
+if (prettyLogsEnabled) {
+  pinoHttpConfig.transport = {
+    target: "pino-pretty",
+    options: {
+      colorize: true,
+      translateTime: false,
+      singleLine: true,
+      // keep level for coloring but drop other noisy metadata
+      ignore: "pid,req,res,context,name,time",
     },
-    }),
+  };
-  ],
+}
+
+@Global()
+@Module({
+  imports: [LoggerModule.forRoot({ pinoHttp: pinoHttpConfig })],
   exports: [LoggerModule],
 })
 export class LoggingModule {}

apps/bff/src/core/security/middleware/csrf.middleware.ts

@@ -31,17 +31,14 @@ type CsrfRequest = Omit<BaseExpressRequest, "cookies"> & {
  */
 @Injectable()
 export class CsrfMiddleware implements NestMiddleware {
-  private readonly isProduction: boolean;
   private readonly exemptPaths: Set<string>;
   private readonly safeMethods: Set<string>;
 
   constructor(
     private readonly csrfService: CsrfService,
-    private readonly configService: ConfigService,
+    _configService: ConfigService,
     @Inject(Logger) private readonly logger: Logger
   ) {
-    this.isProduction = this.configService.get("NODE_ENV") === "production";
-
     // Paths that don't require CSRF protection
     this.exemptPaths = new Set([
       "/api/auth/login",
@@ -94,7 +91,7 @@ export class CsrfMiddleware implements NestMiddleware {
     return false;
   }
 
-  private validateCsrfToken(req: CsrfRequest, res: Response, next: NextFunction): void {
+  private validateCsrfToken(req: CsrfRequest, _res: Response, next: NextFunction): void {
     const token = this.extractTokenFromRequest(req);
     const secret = this.extractSecretFromCookie(req);
     const sessionId = req.user?.sessionId || this.extractSessionId(req);

apps/bff/src/core/security/services/csrf.service.ts

@@ -7,13 +7,13 @@ export interface CsrfTokenData {
   token: string;
   secret: string;
   expiresAt: Date;
-  sessionId?: string;
+  sessionId?: string | undefined;
-  userId?: string;
+  userId?: string | undefined;
 }
 
 export interface CsrfValidationResult {
   isValid: boolean;
-  reason?: string;
+  reason?: string | undefined;
 }
 
 export interface CsrfTokenStats {
@@ -191,7 +191,7 @@ export class CsrfService {
   }
 
   private hashToken(token: string): string {
-    return crypto.createHash("sha256").update(token).digest("hex").substring(0, 16);
+    return crypto.createHash("sha256").update(token).digest("hex").slice(0, 16);
   }
 
   private constantTimeEquals(a: string, b: string): boolean {

apps/bff/src/core/utils/error.util.ts

@@ -11,7 +11,7 @@ export function isErrorWithMessage(error: unknown): error is Error {
     typeof error === "object" &&
     error !== null &&
     Object.hasOwn(error, "message") &&
-    typeof (error as Record<string, unknown>).message === "string"
+    typeof (error as Record<string, unknown>)["message"] === "string"
   );
 }
 
@@ -19,8 +19,8 @@ export function isErrorWithMessage(error: unknown): error is Error {
  * Enhanced error type with common error properties
  */
 interface EnhancedError extends Error {
-  code?: string;
+  code?: string | undefined;
-  statusCode?: number;
+  statusCode?: number | undefined;
   cause?: unknown;
 }
 

apps/bff/src/core/utils/retry.util.ts

@@ -71,8 +71,10 @@ export function calculateBackoffDelay(
 /**
  * Promise-based sleep utility
  */
-export function sleep(ms: number): Promise<void> {
+export async function sleep(ms: number): Promise<void> {
-  return new Promise(resolve => setTimeout(resolve, ms));
+  return new Promise(resolve => {
+    setTimeout(resolve, ms);
+  });
 }
 
 /**

apps/bff/src/infra/audit/audit.service.ts

@@ -22,16 +22,28 @@ export enum AuditAction {
 }
 
 export interface AuditLogData {
-  userId?: string;
+  userId?: string | undefined;
   action: AuditAction;
-  resource?: string;
+  resource?: string | undefined;
-  details?: Record<string, unknown> | string | number | boolean | null;
+  details?: Record<string, unknown> | string | number | boolean | null | undefined;
-  ipAddress?: string;
+  ipAddress?: string | undefined;
-  userAgent?: string;
+  userAgent?: string | undefined;
-  success?: boolean;
+  success?: boolean | undefined;
-  error?: string;
+  error?: string | undefined;
 }
 
+/**
+ * Minimal request shape for audit logging.
+ * Compatible with Express Request but only requires the fields needed for IP/UA extraction.
+ * Must be compatible with RequestContextLike from request-context.util.ts.
+ */
+export type AuditRequest = {
+  headers?: Record<string, string | string[] | undefined> | undefined;
+  ip?: string | undefined;
+  connection?: { remoteAddress?: string | undefined } | undefined;
+  socket?: { remoteAddress?: string | undefined } | undefined;
+};
+
 @Injectable()
 export class AuditService {
   constructor(
@@ -41,23 +53,24 @@ export class AuditService {
 
   async log(data: AuditLogData): Promise<void> {
     try {
-      await this.prisma.auditLog.create({
+      const createData: Parameters<typeof this.prisma.auditLog.create>[0]["data"] = {
-        data: {
-          userId: data.userId,
         action: data.action,
-          resource: data.resource,
-          details:
-            data.details === undefined
-              ? undefined
-              : data.details === null
-                ? Prisma.JsonNull
-                : (JSON.parse(JSON.stringify(data.details)) as Prisma.InputJsonValue),
-          ipAddress: data.ipAddress,
-          userAgent: data.userAgent,
         success: data.success ?? true,
-          error: data.error,
+      };
-        },
+
-      });
+      if (data.userId !== undefined) createData.userId = data.userId;
+      if (data.resource !== undefined) createData.resource = data.resource;
+      if (data.ipAddress !== undefined) createData.ipAddress = data.ipAddress;
+      if (data.userAgent !== undefined) createData.userAgent = data.userAgent;
+      if (data.error !== undefined) createData.error = data.error;
+      if (data.details !== undefined) {
+        createData.details =
+          data.details === null
+            ? Prisma.JsonNull
+            : (JSON.parse(JSON.stringify(data.details)) as Prisma.InputJsonValue);
+      }
+
+      await this.prisma.auditLog.create({ data: createData });
     } catch (error) {
       this.logger.error("Audit logging failed", {
         errorType: error instanceof Error ? error.constructor.name : "Unknown",
@@ -70,12 +83,7 @@ export class AuditService {
     action: AuditAction,
     userId?: string,
     details?: Record<string, unknown> | string | number | boolean | null,
-    request?: {
+    request?: AuditRequest,
-      headers?: Record<string, string | string[] | undefined>;
-      ip?: string;
-      connection?: { remoteAddress?: string };
-      socket?: { remoteAddress?: string };
-    },
     success: boolean = true,
     error?: string
   ): Promise<void> {

apps/bff/src/infra/cache/cache.service.ts

@@ -78,22 +78,23 @@ export class CacheService {
    */
   async delPattern(pattern: string): Promise<void> {
     const pipeline = this.redis.pipeline();
-    let pending = 0;
+    const state = { pending: 0 };
 
     const flush = async () => {
-      if (pending === 0) {
+      if (state.pending === 0) {
         return;
       }
       await pipeline.exec();
-      pending = 0;
+      // eslint-disable-next-line require-atomic-updates -- flush is called sequentially, no concurrent access
+      state.pending = 0;
     };
 
     await this.scanPattern(pattern, async keys => {
-      keys.forEach(key => {
+      for (const key of keys) {
         pipeline.del(key);
-        pending += 1;
+        state.pending += 1;
-      });
+      }
-      if (pending >= 1000) {
+      if (state.pending >= 1000) {
         await flush();
       }
     });
@@ -122,9 +123,9 @@ export class CacheService {
     let total = 0;
     await this.scanPattern(pattern, async keys => {
       const pipeline = this.redis.pipeline();
-      keys.forEach(key => {
+      for (const key of keys) {
         pipeline.memory("USAGE", key);
-      });
+      }
       const results = await pipeline.exec();
       if (!results) {
         return;

apps/bff/src/infra/cache/distributed-lock.service.ts

@@ -65,7 +65,7 @@ export class DistributedLockService {
         return {
           key: lockKey,
           token,
-          release: () => this.release(lockKey, token),
+          release: async () => this.release(lockKey, token),
         };
       }
 
@@ -183,7 +183,9 @@ export class DistributedLockService {
   /**
    * Delay helper
    */
-  private delay(ms: number): Promise<void> {
+  private async delay(ms: number): Promise<void> {
-    return new Promise(resolve => setTimeout(resolve, ms));
+    return new Promise(resolve => {
+      setTimeout(resolve, ms);
+    });
   }
 }

apps/bff/src/infra/database/prisma.service.ts

@@ -17,12 +17,11 @@ import { PrismaPg } from "@prisma/adapter-pg";
 export class PrismaService extends PrismaClient implements OnModuleInit, OnModuleDestroy {
   private readonly logger = new Logger(PrismaService.name);
   private readonly pool: Pool;
-  private readonly instanceTag: string;
   private destroyCalls = 0;
   private poolEnded = false;
 
   constructor() {
-    const connectionString = process.env.DATABASE_URL;
+    const connectionString = process.env["DATABASE_URL"];
     if (!connectionString) {
       throw new Error("DATABASE_URL environment variable is required");
     }
@@ -43,7 +42,6 @@ export class PrismaService extends PrismaClient implements OnModuleInit, OnModul
     super({ adapter });
 
     this.pool = pool;
-    this.instanceTag = `${process.pid}:${Date.now()}`;
   }
 
   async onModuleInit() {

apps/bff/src/infra/database/services/distributed-transaction.service.ts

@@ -24,8 +24,8 @@ export interface DistributedTransactionResult<
   TStepResults extends StepResultMap = StepResultMap,
 > {
   success: boolean;
-  data?: TData;
+  data?: TData | undefined;
-  error?: string;
+  error?: string | undefined;
   duration: number;
   stepsExecuted: number;
   stepsRolledBack: number;
@@ -254,7 +254,7 @@ export class DistributedTransactionService {
           databaseOperation,
           {
             description: `${options.description} - Database Operations`,
-            timeout: options.timeout,
+            ...(options.timeout !== undefined && { timeout: options.timeout }),
           }
         );
 
@@ -305,7 +305,7 @@ export class DistributedTransactionService {
           databaseOperation,
           {
             description: `${options.description} - Database Operations`,
-            timeout: options.timeout,
+            ...(options.timeout !== undefined && { timeout: options.timeout }),
           }
         );
 
@@ -442,6 +442,6 @@ export class DistributedTransactionService {
   }
 
   private generateTransactionId(): string {
-    return `dtx_${Date.now()}_${Math.random().toString(36).substring(2, 9)}`;
+    return `dtx_${Date.now()}_${Math.random().toString(36).slice(2, 9)}`;
   }
 }

apps/bff/src/infra/database/services/transaction.service.ts

@@ -28,36 +28,41 @@ export interface TransactionOptions {
    * Maximum time to wait for transaction to complete (ms)
    * Default: 30 seconds
    */
-  timeout?: number;
+  timeout?: number | undefined;
 
   /**
    * Maximum number of retry attempts on serialization failures
    * Default: 3
    */
-  maxRetries?: number;
+  maxRetries?: number | undefined;
 
   /**
    * Custom isolation level for the transaction
    * Default: ReadCommitted
    */
-  isolationLevel?: "ReadUncommitted" | "ReadCommitted" | "RepeatableRead" | "Serializable";
+  isolationLevel?:
+    | "ReadUncommitted"
+    | "ReadCommitted"
+    | "RepeatableRead"
+    | "Serializable"
+    | undefined;
 
   /**
    * Description of the transaction for logging
    */
-  description?: string;
+  description?: string | undefined;
 
   /**
    * Whether to automatically rollback external operations on database rollback
    * Default: true
    */
-  autoRollback?: boolean;
+  autoRollback?: boolean | undefined;
 }
 
 export interface TransactionResult<T> {
   success: boolean;
-  data?: T;
+  data?: T | undefined;
-  error?: string;
+  error?: string | undefined;
   duration: number;
   operationsCount: number;
   rollbacksExecuted: number;
@@ -289,8 +294,10 @@ export class TransactionService {
 
     // Execute rollbacks in reverse order (LIFO)
     for (let i = context.rollbackActions.length - 1; i >= 0; i--) {
+      const rollbackAction = context.rollbackActions[i];
+      if (!rollbackAction) continue;
       try {
-        await context.rollbackActions[i]();
+        await rollbackAction();
         rollbacksExecuted++;
         this.logger.debug(`Rollback ${i + 1} completed [${context.id}]`);
       } catch (rollbackError) {
@@ -321,11 +328,13 @@ export class TransactionService {
   }
 
   private async delay(ms: number): Promise<void> {
-    return new Promise(resolve => setTimeout(resolve, ms));
+    return new Promise(resolve => {
+      setTimeout(resolve, ms);
+    });
   }
 
   private generateTransactionId(): string {
-    return `tx_${Date.now()}_${Math.random().toString(36).substring(2, 9)}`;
+    return `tx_${Date.now()}_${Math.random().toString(36).slice(2, 9)}`;
   }
 
   /**

apps/bff/src/infra/email/providers/sendgrid.provider.ts

@@ -19,8 +19,8 @@ export interface ProviderSendOptions {
 
 export interface SendGridErrorDetail {
   message: string;
-  field?: string;
+  field?: string | undefined;
-  help?: string;
+  help?: string | undefined;
 }
 
 export interface ParsedSendGridError {
@@ -215,8 +215,8 @@ export class SendGridEmailProvider implements OnModuleInit {
   private maskEmail(email: string | string[]): string | string[] {
     const mask = (e: string): string => {
       const [local, domain] = e.split("@");
-      if (!domain) return "***";
+      if (!domain || !local) return "***";
-      const maskedLocal = local.length > 2 ? `${local[0]}***${local[local.length - 1]}` : "***";
+      const maskedLocal = local.length > 2 ? `${local[0]}***${local.at(-1)}` : "***";
       return `${maskedLocal}@${domain}`;
     };
 

apps/bff/src/infra/queue/queue.module.ts

@@ -17,7 +17,7 @@ function parseRedisConnection(redisUrl: string) {
       host: url.hostname,
       port: Number(url.port || (isTls ? 6380 : 6379)),
       password: url.password || undefined,
-      ...(db !== undefined ? { db } : {}),
+      ...(db === undefined ? {} : { db }),
       ...(isTls ? { tls: {} } : {}),
     } as Record<string, unknown>;
   } catch {

apps/bff/src/infra/queue/services/salesforce-queue-degradation.service.ts

@@ -11,7 +11,7 @@ export type DegradationReason = "rate-limit" | "usage-threshold" | "queue-pressu
 export interface SalesforceDegradationSnapshot {
   degraded: boolean;
   reason: DegradationReason | null;
-  cooldownExpiresAt?: Date;
+  cooldownExpiresAt?: Date | undefined;
   usagePercent: number;
 }
 
@@ -118,8 +118,7 @@ export class SalesforceQueueDegradationService {
       this.activateDegradeWindow("usage-threshold");
     }
 
-    const threshold = this.usageWarningLevels
+    const threshold = [...this.usageWarningLevels]
-      .slice()
       .reverse()
       .find(level => usagePercent >= level && level > this.highestUsageWarningIssued);
 

apps/bff/src/infra/queue/services/salesforce-queue-metrics.service.ts

@@ -8,16 +8,16 @@ export interface SalesforceRouteMetricsInternal {
   label: string;
   totalRequests: number;
   failedRequests: number;
-  lastSuccessTime?: Date;
+  lastSuccessTime?: Date | undefined;
-  lastErrorTime?: Date;
+  lastErrorTime?: Date | undefined;
 }
 
 export interface SalesforceRouteMetricsSnapshot {
   totalRequests: number;
   failedRequests: number;
   successRate: number;
-  lastSuccessTime?: Date;
+  lastSuccessTime?: Date | undefined;
-  lastErrorTime?: Date;
+  lastErrorTime?: Date | undefined;
 }
 
 export interface SalesforceQueueMetricsData {
@@ -29,9 +29,9 @@ export interface SalesforceQueueMetricsData {
   averageWaitTime: number;
   averageExecutionTime: number;
   dailyApiUsage: number;
-  lastRequestTime?: Date;
+  lastRequestTime?: Date | undefined;
-  lastErrorTime?: Date;
+  lastErrorTime?: Date | undefined;
-  lastRateLimitTime?: Date;
+  lastRateLimitTime?: Date | undefined;
 }
 
 @Injectable()
@@ -52,7 +52,10 @@ export class SalesforceQueueMetricsService {
     dailyApiUsage: 0,
   };
 
-  constructor(@Inject(Logger) private readonly logger: Logger) {}
+  constructor(@Inject(Logger) _logger: Logger) {
+    // Logger available for future use in metrics logging
+    void _logger;
+  }
 
   /**
    * Get current metrics data

apps/bff/src/infra/queue/services/salesforce-request-queue.service.ts

@@ -22,13 +22,13 @@ export interface SalesforceQueueMetrics {
   averageWaitTime: number;
   averageExecutionTime: number;
   dailyApiUsage: number;
-  lastRequestTime?: Date;
+  lastRequestTime?: Date | undefined;
-  lastErrorTime?: Date;
+  lastErrorTime?: Date | undefined;
-  lastRateLimitTime?: Date;
+  lastRateLimitTime?: Date | undefined;
-  dailyApiLimit?: number;
+  dailyApiLimit?: number | undefined;
-  dailyUsagePercent?: number;
+  dailyUsagePercent?: number | undefined;
-  routeBreakdown?: Record<string, SalesforceRouteMetricsSnapshot>;
+  routeBreakdown?: Record<string, SalesforceRouteMetricsSnapshot> | undefined;
-  degradation?: SalesforceDegradationSnapshot;
+  degradation?: SalesforceDegradationSnapshot | undefined;
 }
 
 export interface SalesforceRequestOptions {
@@ -480,7 +480,9 @@ export class SalesforceRequestQueueService implements OnModuleInit, OnModuleDest
           error: lastError.message,
         });
 
-        await new Promise(resolve => setTimeout(resolve, delay));
+        await new Promise(resolve => {
+          setTimeout(resolve, delay);
+        });
       }
     }
 

apps/bff/src/infra/queue/services/whmcs-request-queue.service.ts

@@ -35,10 +35,10 @@ export interface WhmcsQueueMetrics {
 }
 
 export interface WhmcsRequestOptions {
-  priority?: number; // Higher number = higher priority (0-10)
+  priority?: number | undefined; // Higher number = higher priority (0-10)
-  timeout?: number; // Request timeout in ms
+  timeout?: number | undefined; // Request timeout in ms
-  retryAttempts?: number; // Number of retry attempts
+  retryAttempts?: number | undefined; // Number of retry attempts
-  retryDelay?: number; // Base delay between retries in ms
+  retryDelay?: number | undefined; // Base delay between retries in ms
 }
 
 /**

apps/bff/src/infra/realtime/realtime.pubsub.ts

@@ -72,7 +72,7 @@ export class RealtimePubSubService implements OnModuleInit, OnModuleDestroy {
     }
   }
 
-  publish(message: RealtimePubSubMessage): Promise<number> {
+  async publish(message: RealtimePubSubMessage): Promise<number> {
     return this.redis.publish(this.CHANNEL, JSON.stringify(message));
   }
 

apps/bff/src/infra/realtime/realtime.service.ts

@@ -109,7 +109,7 @@ export class RealtimeService {
     }
 
     const evt = this.buildMessage(message.event, message.data);
-    set.forEach(observer => {
+    for (const observer of set) {
       try {
         observer.next(evt);
       } catch (error) {
@@ -118,7 +118,7 @@ export class RealtimeService {
           error: extractErrorMessage(error),
         });
       }
-    });
+    }
   }
 
   private buildMessage<TEvent extends string>(event: TEvent, data: unknown): MessageEvent {

apps/bff/src/integrations/freebit/services/freebit-account.service.ts

@@ -35,8 +35,8 @@ export class FreebitAccountService {
 
       const config = this.auth.getConfig();
       const configured = config.detailsEndpoint || "/master/getAcnt/";
-      const candidates = Array.from(
+      const candidates = [
-        new Set([
+        ...new Set([
           configured,
           configured.replace(/\/$/, ""),
           "/master/getAcnt/",
@@ -53,8 +53,8 @@ export class FreebitAccountService {
           "/mvno/getInfo",
           "/master/getDetail/",
           "/master/getDetail",
-        ])
+        ]),
-      );
+      ];
 
       let response: FreebitAccountDetailsResponse | undefined;
       let lastError: unknown;

apps/bff/src/integrations/freebit/services/freebit-auth.service.ts

@@ -80,9 +80,9 @@ export class FreebitAuthService {
       }
 
       const data = (await response.json()) as FreebitAuthResponse;
-      const resultCode = data?.resultCode != null ? String(data.resultCode).trim() : undefined;
+      const resultCode = data?.resultCode == null ? undefined : String(data.resultCode).trim();
       const statusCode =
-        data?.status?.statusCode != null ? String(data.status.statusCode).trim() : undefined;
+        data?.status?.statusCode == null ? undefined : String(data.status.statusCode).trim();
 
       if (resultCode !== "100") {
         throw new FreebitError(

apps/bff/src/integrations/freebit/services/freebit-cancellation.service.ts

@@ -30,7 +30,7 @@ export class FreebitCancellationService {
       await this.rateLimiter.executeWithSpacing(account, "cancellation", async () => {
         const request: Omit<FreebitCancelPlanRequest, "authKey"> = {
           account,
-          runTime: scheduledAt,
+          ...(scheduledAt !== undefined && { runTime: scheduledAt }),
         };
 
         this.logger.log(`Cancelling SIM plan via PA05-04 for account ${account}`, {
@@ -75,7 +75,7 @@ export class FreebitCancellationService {
         const request: Omit<FreebitCancelAccountRequest, "authKey"> = {
           kind: "MVNO",
           account,
-          runDate,
+          ...(runDate !== undefined && { runDate }),
         };
 
         this.logger.log(`Cancelling SIM account via PA02-04 for account ${account}`, {

apps/bff/src/integrations/freebit/services/freebit-client.service.ts

@@ -57,7 +57,7 @@ export class FreebitClientService {
           });
 
           if (!response.ok) {
-            const isProd = process.env.NODE_ENV === "production";
+            const isProd = process.env["NODE_ENV"] === "production";
             const bodySnippet = isProd ? undefined : await this.safeReadBodySnippet(response);
             this.logger.error("Freebit API HTTP error", {
               url,
@@ -78,7 +78,7 @@ export class FreebitClientService {
           const statusCode = this.normalizeResultCode(responseData.status?.statusCode);
 
           if (resultCode && resultCode !== "100") {
-            const isProd = process.env.NODE_ENV === "production";
+            const isProd = process.env["NODE_ENV"] === "production";
             this.logger.warn("Freebit API returned error response", {
               url,
               resultCode,
@@ -166,7 +166,7 @@ export class FreebitClientService {
           const statusCode = this.normalizeResultCode(responseData.status?.statusCode);
 
           if (resultCode && resultCode !== "100") {
-            const isProd = process.env.NODE_ENV === "production";
+            const isProd = process.env["NODE_ENV"] === "production";
             this.logger.error("Freebit API returned error result code", {
               url,
               resultCode,

apps/bff/src/integrations/freebit/services/freebit-error.service.ts

@@ -2,9 +2,9 @@
  * Custom error class for Freebit API errors
  */
 export class FreebitError extends Error {
-  public readonly resultCode?: string | number;
+  public readonly resultCode?: string | number | undefined;
-  public readonly statusCode?: string | number;
+  public readonly statusCode?: string | number | undefined;
-  public readonly statusMessage?: string;
+  public readonly statusMessage?: string | undefined;
 
   constructor(
     message: string,

apps/bff/src/integrations/freebit/services/freebit-esim.service.ts

@@ -86,7 +86,7 @@ export class FreebitEsimService {
         account,
         eid: newEid,
         addKind: "R",
-        planCode: options.planCode,
+        ...(options.planCode !== undefined && { planCode: options.planCode }),
       };
 
       await this.client.makeAuthenticatedRequest<FreebitEsimAddAccountResponse, typeof request>(

apps/bff/src/integrations/freebit/services/freebit-mapper.service.ts

@@ -187,11 +187,12 @@ export class FreebitMapperService {
       throw new Error("No traffic data in response");
     }
 
-    const todayUsageKb = parseInt(response.traffic.today, 10) || 0;
+    const todayUsageKb = Number.parseInt(response.traffic.today, 10) || 0;
     const recentDaysData = response.traffic.inRecentDays.split(",").map((usage, index) => ({
-      date: new Date(Date.now() - (index + 1) * 24 * 60 * 60 * 1000).toISOString().split("T")[0],
+      date:
-      usageKb: parseInt(usage, 10) || 0,
+        new Date(Date.now() - (index + 1) * 24 * 60 * 60 * 1000).toISOString().split("T")[0] ?? "",
-      usageMb: Math.round(((parseInt(usage, 10) || 0) / 1024) * 100) / 100,
+      usageKb: Number.parseInt(usage, 10) || 0,
+      usageMb: Math.round(((Number.parseInt(usage, 10) || 0) / 1024) * 100) / 100,
     }));
 
     return {
@@ -216,8 +217,8 @@ export class FreebitMapperService {
       totalAdditions: Number(response.total) || 0,
       additionCount: Number(response.count) || 0,
       history: response.quotaHistory.map(item => ({
-        quotaKb: parseInt(item.quota, 10),
+        quotaKb: Number.parseInt(item.quota, 10),
-        quotaMb: Math.round((parseInt(item.quota, 10) / 1024) * 100) / 100,
+        quotaMb: Math.round((Number.parseInt(item.quota, 10) / 1024) * 100) / 100,
         addedDate: item.date,
         expiryDate: item.expire,
         campaignCode: item.quotaCode,
@@ -259,9 +260,9 @@ export class FreebitMapperService {
       return null;
     }
 
-    const year = parseInt(dateString.substring(0, 4), 10);
+    const year = Number.parseInt(dateString.slice(0, 4), 10);
-    const month = parseInt(dateString.substring(4, 6), 10) - 1; // Month is 0-indexed
+    const month = Number.parseInt(dateString.slice(4, 6), 10) - 1; // Month is 0-indexed
-    const day = parseInt(dateString.substring(6, 8), 10);
+    const day = Number.parseInt(dateString.slice(6, 8), 10);
 
     return new Date(year, month, day);
   }

apps/bff/src/integrations/freebit/services/freebit-operations.service.ts

@@ -111,7 +111,7 @@ export class FreebitOperationsService {
     account: string,
     newPlanCode: string,
     options: { assignGlobalIp?: boolean; scheduledAt?: string } = {}
-  ): Promise<{ ipv4?: string; ipv6?: string }> {
+  ): Promise<{ ipv4?: string | undefined; ipv6?: string | undefined }> {
     const normalizedAccount = this.normalizeAccount(account);
     return this.planService.changeSimPlan(normalizedAccount, newPlanCode, options);
   }

apps/bff/src/integrations/freebit/services/freebit-plan.service.ts

@@ -37,7 +37,7 @@ export class FreebitPlanService {
     account: string,
     newPlanCode: string,
     options: { assignGlobalIp?: boolean; scheduledAt?: string } = {}
-  ): Promise<{ ipv4?: string; ipv6?: string }> {
+  ): Promise<{ ipv4?: string | undefined; ipv6?: string | undefined }> {
     try {
       return await this.rateLimiter.executeWithSpacing(account, "plan", async () => {
         // First, get current SIM details to log for debugging
@@ -127,17 +127,17 @@ export class FreebitPlanService {
       };
 
       if (error instanceof Error) {
-        errorDetails.errorName = error.name;
+        errorDetails["errorName"] = error.name;
-        errorDetails.errorMessage = error.message;
+        errorDetails["errorMessage"] = error.message;
 
         if ("resultCode" in error) {
-          errorDetails.resultCode = error.resultCode;
+          errorDetails["resultCode"] = (error as Record<string, unknown>)["resultCode"];
         }
         if ("statusCode" in error) {
-          errorDetails.statusCode = error.statusCode;
+          errorDetails["statusCode"] = (error as Record<string, unknown>)["statusCode"];
         }
         if ("statusMessage" in error) {
-          errorDetails.statusMessage = error.statusMessage;
+          errorDetails["statusMessage"] = (error as Record<string, unknown>)["statusMessage"];
         }
       }
 

apps/bff/src/integrations/freebit/services/freebit-rate-limiter.service.ts

@@ -155,7 +155,7 @@ export class FreebitRateLimiterService {
       const parsed: OperationTimestamps = {};
       for (const [field, value] of Object.entries(raw)) {
         const num = Number(value);
-        if (!isNaN(num)) {
+        if (!Number.isNaN(num)) {
           parsed[field as keyof OperationTimestamps] = num;
         }
       }

apps/bff/src/integrations/freebit/services/freebit-usage.service.ts

@@ -62,8 +62,8 @@ export class FreebitUsageService {
       const baseRequest: Omit<FreebitTopUpRequest, "authKey"> = {
         account,
         quota: quotaKb,
-        quotaCode: options.campaignCode,
+        ...(options.campaignCode !== undefined && { quotaCode: options.campaignCode }),
-        expire: options.expiryDate,
+        ...(options.expiryDate !== undefined && { expire: options.expiryDate }),
       };
 
       const scheduled = !!options.scheduledAt;

apps/bff/src/integrations/freebit/services/freebit-voice.service.ts

@@ -14,9 +14,9 @@ import type {
 } from "../interfaces/freebit.types.js";
 
 export interface VoiceFeatures {
-  voiceMailEnabled?: boolean;
+  voiceMailEnabled?: boolean | undefined;
-  callWaitingEnabled?: boolean;
+  callWaitingEnabled?: boolean | undefined;
-  internationalRoamingEnabled?: boolean;
+  internationalRoamingEnabled?: boolean | undefined;
 }
 
 /**

apps/bff/src/integrations/japanpost/services/japanpost-connection.service.ts

@@ -37,9 +37,9 @@ interface ConfigValidationError {
  * Japan Post API error response format
  */
 interface JapanPostErrorResponse {
-  request_id?: string;
+  request_id?: string | undefined;
-  error_code?: string;
+  error_code?: string | undefined;
-  message?: string;
+  message?: string | undefined;
 }
 
 @Injectable()

apps/bff/src/integrations/salesforce/config/order-field-map.service.ts

@@ -7,7 +7,7 @@ import {
   type SalesforceOrderFieldMap,
 } from "@customer-portal/domain/orders/providers";
 
-const unique = (values: string[]): string[] => Array.from(new Set(values));
+const unique = (values: string[]): string[] => [...new Set(values)];
 
 const SECTION_PREFIX: Record<keyof SalesforceOrderFieldMap, string> = {
   order: "ORDER",

apps/bff/src/integrations/salesforce/events/account-events.subscriber.ts

@@ -80,7 +80,7 @@ export class AccountEventsSubscriber implements OnModuleInit {
    */
   private async handleAccountEvent(
     channel: string,
-    subscription: { topicName?: string },
+    _subscription: { topicName?: string },
     callbackType: string,
     data: unknown
   ): Promise<void> {
@@ -118,10 +118,10 @@ export class AccountEventsSubscriber implements OnModuleInit {
     if (this.accountNotificationHandler && (eligibilityStatus || verificationStatus)) {
       void this.accountNotificationHandler.processAccountEvent({
         accountId,
-        eligibilityStatus,
+        eligibilityStatus: eligibilityStatus ?? null,
-        eligibilityValue: undefined,
+        eligibilityValue: null,
-        verificationStatus,
+        verificationStatus: verificationStatus ?? null,
-        verificationRejectionMessage: rejectionMessage,
+        verificationRejectionMessage: rejectionMessage ?? null,
       });
     }
   }

apps/bff/src/integrations/salesforce/events/case-events.subscriber.ts

@@ -63,7 +63,7 @@ export class CaseEventsSubscriber implements OnModuleInit {
    */
   private async handleCaseEvent(
     channel: string,
-    subscription: { topicName?: string },
+    _subscription: { topicName?: string },
     callbackType: string,
     data: unknown
   ): Promise<void> {

apps/bff/src/integrations/salesforce/events/catalog-cdc.subscriber.ts

@@ -127,7 +127,7 @@ export class CatalogCdcSubscriber implements OnModuleInit {
 
   private async handlePricebookEvent(
     channel: string,
-    subscription: { topicName?: string },
+    _subscription: { topicName?: string },
     callbackType: string,
     data: unknown
   ): Promise<void> {

apps/bff/src/integrations/salesforce/events/order-cdc.subscriber.ts

@@ -111,7 +111,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
 
   private async handleOrderEvent(
     channel: string,
-    subscription: { topicName?: string },
+    _subscription: { topicName?: string },
     callbackType: string,
     data: unknown
   ): Promise<void> {
@@ -141,7 +141,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
       this.logger.debug("Order CDC: only internal field changes; skipping cache invalidation", {
         channel,
         orderId,
-        changedFields: Array.from(changedFields),
+        changedFields: [...changedFields],
       });
       return;
     }
@@ -150,7 +150,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
       channel,
       orderId,
       accountId,
-      changedFields: Array.from(changedFields),
+      changedFields: [...changedFields],
     });
 
     await this.invalidateOrderCaches(orderId, accountId);
@@ -222,7 +222,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
 
   private async handleOrderItemEvent(
     channel: string,
-    subscription: { topicName?: string },
+    _subscription: { topicName?: string },
     callbackType: string,
     data: unknown
   ): Promise<void> {
@@ -245,7 +245,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
       this.logger.debug("OrderItem CDC: only internal field changes; skipping", {
         channel,
         orderId,
-        changedFields: Array.from(changedFields),
+        changedFields: [...changedFields],
       });
       return;
     }
@@ -253,7 +253,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
     this.logger.log("OrderItem CDC: invalidating order cache", {
       channel,
       orderId,
-      changedFields: Array.from(changedFields),
+      changedFields: [...changedFields],
     });
 
     await this.invalidateOrderCaches(orderId, accountId);
@@ -291,7 +291,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
       return true;
     }
 
-    const customerFacingChanges = Array.from(changedFields).filter(
+    const customerFacingChanges = [...changedFields].filter(
       field => !INTERNAL_ORDER_FIELDS.has(field)
     );
 
@@ -303,7 +303,7 @@ export class OrderCdcSubscriber implements OnModuleInit {
       return true; // Safe default
     }
 
-    const customerFacingChanges = Array.from(changedFields).filter(
+    const customerFacingChanges = [...changedFields].filter(
       field => !INTERNAL_ORDER_ITEM_FIELDS.has(field)
     );
 

apps/bff/src/integrations/salesforce/events/shared/pubsub.utils.ts

@@ -98,8 +98,8 @@ export function extractChangedFields(payload: Record<string, unknown> | undefine
 
   // CDC provides changed fields in different formats depending on API version
   const changedFieldsArray =
-    (payload.changedFields as string[] | undefined) ||
+    (payload["changedFields"] as string[] | undefined) ||
-    (payload.changeOrigin as { changedFields?: string[] })?.changedFields ||
+    (payload["changeOrigin"] as { changedFields?: string[] } | undefined)?.changedFields ||
     [];
 
   return new Set([

apps/bff/src/integrations/salesforce/salesforce.service.ts

@@ -45,7 +45,7 @@ export class SalesforceService implements OnModuleInit {
       }
     } catch (error) {
       const nodeEnv =
-        this.configService.get<string>("NODE_ENV") || process.env.NODE_ENV || "development";
+        this.configService.get<string>("NODE_ENV") || process.env["NODE_ENV"] || "development";
       const isProd = nodeEnv === "production";
       if (isProd) {
         this.logger.error("Failed to initialize Salesforce connection");
@@ -63,15 +63,19 @@ export class SalesforceService implements OnModuleInit {
     return this.accountService.findByCustomerNumber(customerNumber);
   }
 
-  async findAccountWithDetailsByCustomerNumber(
+  async findAccountWithDetailsByCustomerNumber(customerNumber: string): Promise<{
-    customerNumber: string
+    id: string;
-  ): Promise<{ id: string; WH_Account__c?: string | null; Name?: string | null } | null> {
+    WH_Account__c?: string | null | undefined;
+    Name?: string | null | undefined;
+  } | null> {
     return this.accountService.findWithDetailsByCustomerNumber(customerNumber);
   }
 
-  async getAccountDetails(
+  async getAccountDetails(accountId: string): Promise<{
-    accountId: string
+    id: string;
-  ): Promise<{ id: string; WH_Account__c?: string | null; Name?: string | null } | null> {
+    WH_Account__c?: string | null | undefined;
+    Name?: string | null | undefined;
+  } | null> {
     return this.accountService.getAccountDetails(accountId);
   }
 

apps/bff/src/integrations/salesforce/services/opportunity-resolution.service.ts

@@ -82,7 +82,7 @@ export class OpportunityResolutionService {
   async resolveForOrderPlacement(params: {
     accountId: string | null;
     orderType: OrderTypeValue;
-    existingOpportunityId?: string;
+    existingOpportunityId?: string | undefined;
   }): Promise<string | null> {
     if (!params.accountId) return null;
 

apps/bff/src/integrations/salesforce/services/opportunity/opportunity-mutation.service.ts

@@ -110,9 +110,9 @@ export class OpportunityMutationService {
 
       if (error && typeof error === "object") {
         const err = error as Record<string, unknown>;
-        if (err.errorCode) errorDetails.errorCode = err.errorCode;
+        if (err["errorCode"]) errorDetails["errorCode"] = err["errorCode"];
-        if (err.fields) errorDetails.fields = err.fields;
+        if (err["fields"]) errorDetails["fields"] = err["fields"];
-        if (err.message) errorDetails.rawMessage = err.message;
+        if (err["message"]) errorDetails["rawMessage"] = err["message"];
       }
 
       this.logger.error(errorDetails, "Failed to create Opportunity");
@@ -246,7 +246,7 @@ export class OpportunityMutationService {
   // ==========================================================================
 
   private calculateCloseDate(
-    productType: OpportunityProductTypeValue,
+    _productType: OpportunityProductTypeValue,
     stage: OpportunityStageValue
   ): string {
     const today = new Date();

apps/bff/src/integrations/salesforce/services/opportunity/opportunity-query.service.ts

@@ -39,15 +39,15 @@ export interface InternetCancellationStatusResult {
   stage: OpportunityStageValue;
   isPending: boolean;
   isComplete: boolean;
-  scheduledEndDate?: string;
+  scheduledEndDate?: string | undefined;
-  rentalReturnStatus?: LineReturnStatusValue;
+  rentalReturnStatus?: LineReturnStatusValue | undefined;
 }
 
 export interface SimCancellationStatusResult {
   stage: OpportunityStageValue;
   isPending: boolean;
   isComplete: boolean;
-  scheduledEndDate?: string;
+  scheduledEndDate?: string | undefined;
 }
 
 @Injectable()
@@ -125,8 +125,8 @@ export class OpportunityQueryService {
 
       if (error && typeof error === "object") {
         const err = error as Record<string, unknown>;
-        if (err.errorCode) errorDetails.errorCode = err.errorCode;
+        if (err["errorCode"]) errorDetails["errorCode"] = err["errorCode"];
-        if (err.message) errorDetails.rawMessage = err.message;
+        if (err["message"]) errorDetails["rawMessage"] = err["message"];
       }
 
       this.logger.error(errorDetails, "Failed to find open Opportunity");

apps/bff/src/integrations/salesforce/services/salesforce-account.service.ts

@@ -40,7 +40,7 @@ export class SalesforceAccountService {
   private readonly portalSourceField: string;
   private readonly portalLastSignedInField: string;
   private readonly whmcsAccountField: string;
-  private readonly personAccountRecordTypeId?: string;
+  private readonly personAccountRecordTypeId?: string | undefined;
 
   /**
    * Find Salesforce account by customer number (SF_Account_No__c field)
@@ -65,8 +65,8 @@ export class SalesforceAccountService {
 
   async findWithDetailsByCustomerNumber(customerNumber: string): Promise<{
     id: string;
-    Name?: string | null;
+    Name?: string | null | undefined;
-    WH_Account__c?: string | null;
+    WH_Account__c?: string | null | undefined;
   } | null> {
     const validCustomerNumber = customerNumberSchema.parse(customerNumber);
 
@@ -98,9 +98,11 @@ export class SalesforceAccountService {
    * Get account details including WH_Account__c field
    * Used in signup workflow to check if account is already linked to WHMCS
    */
-  async getAccountDetails(
+  async getAccountDetails(accountId: string): Promise<{
-    accountId: string
+    id: string;
-  ): Promise<{ id: string; WH_Account__c?: string | null; Name?: string | null } | null> {
+    WH_Account__c?: string | null | undefined;
+    Name?: string | null | undefined;
+  } | null> {
     const validAccountId = salesforceIdSchema.parse(accountId);
 
     try {
@@ -196,9 +198,9 @@ export class SalesforceAccountService {
 
     this.logger.debug("Person Account creation payload", {
       recordTypeId: personAccountRecordTypeId,
-      hasFirstName: Boolean(accountPayload.FirstName),
+      hasFirstName: Boolean(accountPayload["FirstName"]),
-      hasLastName: Boolean(accountPayload.LastName),
+      hasLastName: Boolean(accountPayload["LastName"]),
-      hasPersonEmail: Boolean(accountPayload.PersonEmail),
+      hasPersonEmail: Boolean(accountPayload["PersonEmail"]),
     });
 
     try {
@@ -249,18 +251,18 @@ export class SalesforceAccountService {
       if (error && typeof error === "object") {
         const err = error as Record<string, unknown>;
         // jsforce errors often have these properties
-        if (err.errorCode) errorDetails.errorCode = err.errorCode;
+        if (err["errorCode"]) errorDetails["errorCode"] = err["errorCode"];
-        if (err.fields) errorDetails.fields = err.fields;
+        if (err["fields"]) errorDetails["fields"] = err["fields"];
-        if (err.message) errorDetails.rawMessage = err.message;
+        if (err["message"]) errorDetails["rawMessage"] = err["message"];
         // Check for nested error objects
-        if (err.error) errorDetails.nestedError = err.error;
+        if (err["error"]) errorDetails["nestedError"] = err["error"];
         // Log all enumerable properties in development
-        if (process.env.NODE_ENV !== "production") {
+        if (process.env["NODE_ENV"] !== "production") {
-          errorDetails.allProperties = Object.keys(err);
+          errorDetails["allProperties"] = Object.keys(err);
           try {
-            errorDetails.fullError = JSON.stringify(error, null, 2);
+            errorDetails["fullError"] = JSON.stringify(error, null, 2);
           } catch {
-            errorDetails.fullError = errorMessage;
+            errorDetails["fullError"] = errorMessage;
           }
         }
       }
@@ -298,10 +300,14 @@ export class SalesforceAccountService {
         );
       }
 
-      const recordTypeId = recordTypeQuery.records[0].Id;
+      const record = recordTypeQuery.records[0];
+      if (!record) {
+        throw new Error("Person Account RecordType record not found");
+      }
+      const recordTypeId = record.Id;
       this.logger.debug("Found Person Account RecordType", {
         recordTypeId,
-        name: recordTypeQuery.records[0].Name,
+        name: record.Name,
       });
       return recordTypeId;
     } catch (error) {

apps/bff/src/integrations/salesforce/services/salesforce-case.service.ts

@@ -19,19 +19,15 @@ import { extractErrorMessage } from "@bff/core/utils/error.util.js";
 import { CASE_FIELDS } from "../constants/field-maps.js";
 import type { SalesforceResponse } from "@customer-portal/domain/common/providers";
 import type { SupportCase, CaseMessageList } from "@customer-portal/domain/support";
-import type {
-  SalesforceCaseRecord,
-  SalesforceEmailMessage,
-  SalesforceCaseComment,
-} from "@customer-portal/domain/support/providers";
 import {
+  type SalesforceCaseRecord,
+  type SalesforceEmailMessage,
+  type SalesforceCaseComment,
+  type SalesforceCaseOrigin,
   SALESFORCE_CASE_ORIGIN,
   SALESFORCE_CASE_STATUS,
   SALESFORCE_CASE_PRIORITY,
   toSalesforcePriority,
-  type SalesforceCaseOrigin,
-} from "@customer-portal/domain/support/providers";
-import {
   buildCaseByIdQuery,
   buildCaseSelectFields,
   buildCasesForAccountQuery,
@@ -65,11 +61,11 @@ export interface CreateCaseParams {
   /** Case origin - determines visibility and routing */
   origin: SalesforceCaseOrigin;
   /** Priority (defaults to Medium) */
-  priority?: string;
+  priority?: string | undefined;
   /** Optional Salesforce Contact ID */
-  contactId?: string;
+  contactId?: string | undefined;
   /** Optional Opportunity ID for workflow cases */
-  opportunityId?: string;
+  opportunityId?: string | undefined;
 }
 
 /**
@@ -80,9 +76,9 @@ export interface CreateWebCaseParams {
   description: string;
   suppliedEmail: string;
   suppliedName: string;
-  suppliedPhone?: string;
+  suppliedPhone?: string | undefined;
-  origin?: string;
+  origin?: string | undefined;
-  priority?: string;
+  priority?: string | undefined;
 }
 
 @Injectable()

apps/bff/src/integrations/salesforce/services/salesforce-connection.service.ts

@@ -60,8 +60,8 @@ function normalizePrivateKeyInput(
 }
 
 export interface SalesforceSObjectApi {
-  create: (data: Record<string, unknown>) => Promise<{ id?: string }>;
+  create: (data: Record<string, unknown>) => Promise<{ id?: string | undefined }>;
-  update?: (data: Record<string, unknown> & { Id: string }) => Promise<unknown>;
+  update?: ((data: Record<string, unknown> & { Id: string }) => Promise<unknown>) | undefined;
 }
 
 @Injectable()
@@ -114,7 +114,7 @@ export class SalesforceConnection {
 
   private async performConnect(): Promise<void> {
     const nodeEnv =
-      this.configService.get<string>("NODE_ENV") || process.env.NODE_ENV || "development";
+      this.configService.get<string>("NODE_ENV") || process.env["NODE_ENV"] || "development";
     const isProd = nodeEnv === "production";
     const authTimeout = this.configService.get<number>("SF_AUTH_TIMEOUT_MS", 30000);
     const startTime = Date.now();

apps/bff/src/integrations/salesforce/services/salesforce-opportunity.service.ts

@@ -21,11 +21,14 @@ import {
   type OpportunityStageValue,
   type OpportunityProductTypeValue,
   type CancellationOpportunityData,
-  type LineReturnStatusValue,
   type CreateOpportunityRequest,
   type OpportunityRecord,
 } from "@customer-portal/domain/opportunity";
-import { OpportunityQueryService } from "./opportunity/opportunity-query.service.js";
+import {
+  OpportunityQueryService,
+  type InternetCancellationStatusResult,
+  type SimCancellationStatusResult,
+} from "./opportunity/opportunity-query.service.js";
 import { OpportunityCancellationService } from "./opportunity/opportunity-cancellation.service.js";
 import { OpportunityMutationService } from "./opportunity/opportunity-mutation.service.js";
 import type {
@@ -147,63 +150,45 @@ export class SalesforceOpportunityService {
   /**
    * Get Internet cancellation status by WHMCS Service ID
    */
-  async getInternetCancellationStatus(whmcsServiceId: number): Promise<{
+  async getInternetCancellationStatus(
-    stage: OpportunityStageValue;
+    whmcsServiceId: number
-    isPending: boolean;
+  ): Promise<InternetCancellationStatusResult | null> {
-    isComplete: boolean;
-    scheduledEndDate?: string;
-    rentalReturnStatus?: LineReturnStatusValue;
-  } | null> {
     return this.queryService.getInternetCancellationStatus(whmcsServiceId);
   }
 
   /**
    * Get Internet cancellation status by Opportunity ID
    */
-  async getInternetCancellationStatusByOpportunityId(opportunityId: string): Promise<{
+  async getInternetCancellationStatusByOpportunityId(
-    stage: OpportunityStageValue;
+    opportunityId: string
-    isPending: boolean;
+  ): Promise<InternetCancellationStatusResult | null> {
-    isComplete: boolean;
-    scheduledEndDate?: string;
-    rentalReturnStatus?: LineReturnStatusValue;
-  } | null> {
     return this.queryService.getInternetCancellationStatusByOpportunityId(opportunityId);
   }
 
   /**
    * Get SIM cancellation status by WHMCS Service ID
    */
-  async getSimCancellationStatus(whmcsServiceId: number): Promise<{
+  async getSimCancellationStatus(
-    stage: OpportunityStageValue;
+    whmcsServiceId: number
-    isPending: boolean;
+  ): Promise<SimCancellationStatusResult | null> {
-    isComplete: boolean;
-    scheduledEndDate?: string;
-  } | null> {
     return this.queryService.getSimCancellationStatus(whmcsServiceId);
   }
 
   /**
    * Get SIM cancellation status by Opportunity ID
    */
-  async getSimCancellationStatusByOpportunityId(opportunityId: string): Promise<{
+  async getSimCancellationStatusByOpportunityId(
-    stage: OpportunityStageValue;
+    opportunityId: string
-    isPending: boolean;
+  ): Promise<SimCancellationStatusResult | null> {
-    isComplete: boolean;
-    scheduledEndDate?: string;
-  } | null> {
     return this.queryService.getSimCancellationStatusByOpportunityId(opportunityId);
   }
 
   /**
    * @deprecated Use getInternetCancellationStatus or getSimCancellationStatus
    */
-  async getCancellationStatus(whmcsServiceId: number): Promise<{
+  async getCancellationStatus(
-    stage: OpportunityStageValue;
+    whmcsServiceId: number
-    isPending: boolean;
+  ): Promise<InternetCancellationStatusResult | null> {
-    isComplete: boolean;
-    scheduledEndDate?: string;
-    rentalReturnStatus?: LineReturnStatusValue;
-  } | null> {
     return this.queryService.getInternetCancellationStatus(whmcsServiceId);
   }
 

apps/bff/src/integrations/sftp/sftp-client.service.ts

@@ -16,7 +16,7 @@ export interface SftpConfig {
    * The value is compared against ssh2's `hostHash: "sha256"` output.
    * If you paste an OpenSSH-style fingerprint like "SHA256:xxxx", the "SHA256:" prefix is ignored.
    */
-  hostKeySha256?: string;
+  hostKeySha256?: string | undefined;
 }
 
 @Injectable()

apps/bff/src/integrations/whmcs/cache/whmcs-cache.service.ts

@@ -248,14 +248,14 @@ export class WhmcsCacheService {
   async invalidateUserCache(userId: string): Promise<void> {
     try {
       const patterns = [
-        `${this.cacheConfigs.invoices.prefix}:${userId}:*`,
+        `${this.cacheConfigs["invoices"]?.prefix}:${userId}:*`,
-        `${this.cacheConfigs.invoice.prefix}:${userId}:*`,
+        `${this.cacheConfigs["invoice"]?.prefix}:${userId}:*`,
-        `${this.cacheConfigs.subscriptions.prefix}:${userId}:*`,
+        `${this.cacheConfigs["subscriptions"]?.prefix}:${userId}:*`,
-        `${this.cacheConfigs.subscription.prefix}:${userId}:*`,
+        `${this.cacheConfigs["subscription"]?.prefix}:${userId}:*`,
-        `${this.cacheConfigs.subscriptionInvoicesAll.prefix}:${userId}:*`,
+        `${this.cacheConfigs["subscriptionInvoicesAll"]?.prefix}:${userId}:*`,
       ];
 
-      await Promise.all(patterns.map(pattern => this.cacheService.delPattern(pattern)));
+      await Promise.all(patterns.map(async pattern => this.cacheService.delPattern(pattern)));
 
       this.logger.log(`Invalidated all cache for user ${userId}`);
     } catch (error) {
@@ -292,7 +292,7 @@ export class WhmcsCacheService {
         .filter(config => config.tags.includes(tag))
         .map(config => `${config.prefix}:*`);
 
-      await Promise.all(patterns.map(pattern => this.cacheService.delPattern(pattern)));
+      await Promise.all(patterns.map(async pattern => this.cacheService.delPattern(pattern)));
 
       this.logger.log(`Invalidated cache by tag: ${tag}`);
     } catch (error) {
@@ -308,8 +308,8 @@ export class WhmcsCacheService {
   async invalidateInvoice(userId: string, invoiceId: number): Promise<void> {
     try {
       const specificKey = this.buildInvoiceKey(userId, invoiceId);
-      const listPattern = `${this.cacheConfigs.invoices.prefix}:${userId}:*`;
+      const listPattern = `${this.cacheConfigs["invoices"]?.prefix}:${userId}:*`;
-      const subscriptionInvoicesPattern = `${this.cacheConfigs.subscriptionInvoicesAll.prefix}:${userId}:*`;
+      const subscriptionInvoicesPattern = `${this.cacheConfigs["subscriptionInvoicesAll"]?.prefix}:${userId}:*`;
 
       await Promise.all([
         this.cacheService.del(specificKey),
@@ -432,6 +432,10 @@ export class WhmcsCacheService {
   private async set<T>(key: string, data: T, configKey: string): Promise<void> {
     try {
       const config = this.cacheConfigs[configKey];
+      if (!config) {
+        this.logger.warn(`Cache config not found for key ${configKey}`);
+        return;
+      }
       await this.cacheService.set(key, data, config.ttl);
       this.logger.debug(`Cache set: ${key} (TTL: ${config.ttl}s)`);
     } catch (error) {
@@ -443,28 +447,28 @@ export class WhmcsCacheService {
    * Build cache key for invoices list
    */
   private buildInvoicesKey(userId: string, page: number, limit: number, status?: string): string {
-    return `${this.cacheConfigs.invoices.prefix}:${userId}:${page}:${limit}:${status || "all"}`;
+    return `${this.cacheConfigs["invoices"]?.prefix}:${userId}:${page}:${limit}:${status || "all"}`;
   }
 
   /**
    * Build cache key for individual invoice
    */
   private buildInvoiceKey(userId: string, invoiceId: number): string {
-    return `${this.cacheConfigs.invoice.prefix}:${userId}:${invoiceId}`;
+    return `${this.cacheConfigs["invoice"]?.prefix}:${userId}:${invoiceId}`;
   }
 
   /**
    * Build cache key for subscriptions list
    */
   private buildSubscriptionsKey(userId: string): string {
-    return `${this.cacheConfigs.subscriptions.prefix}:${userId}`;
+    return `${this.cacheConfigs["subscriptions"]?.prefix}:${userId}`;
   }
 
   /**
    * Build cache key for individual subscription
    */
   private buildSubscriptionKey(userId: string, subscriptionId: number): string {
-    return `${this.cacheConfigs.subscription.prefix}:${userId}:${subscriptionId}`;
+    return `${this.cacheConfigs["subscription"]?.prefix}:${userId}:${subscriptionId}`;
   }
 
   /**
@@ -476,35 +480,35 @@ export class WhmcsCacheService {
     page: number,
     limit: number
   ): string {
-    return `${this.cacheConfigs.subscriptionInvoices.prefix}:${userId}:${subscriptionId}:${page}:${limit}`;
+    return `${this.cacheConfigs["subscriptionInvoices"]?.prefix}:${userId}:${subscriptionId}:${page}:${limit}`;
   }
 
   /**
    * Build cache key for full subscription invoices list
    */
   private buildSubscriptionInvoicesAllKey(userId: string, subscriptionId: number): string {
-    return `${this.cacheConfigs.subscriptionInvoicesAll.prefix}:${userId}:${subscriptionId}`;
+    return `${this.cacheConfigs["subscriptionInvoicesAll"]?.prefix}:${userId}:${subscriptionId}`;
   }
 
   /**
    * Build cache key for client data
    */
   private buildClientKey(clientId: number): string {
-    return `${this.cacheConfigs.client.prefix}:${clientId}`;
+    return `${this.cacheConfigs["client"]?.prefix}:${clientId}`;
   }
 
   /**
    * Build cache key for client email mapping
    */
   private buildClientEmailKey(email: string): string {
-    return `${this.cacheConfigs.clientEmail.prefix}:${email.toLowerCase()}`;
+    return `${this.cacheConfigs["clientEmail"]?.prefix}:${email.toLowerCase()}`;
   }
 
   /**
    * Build cache key for payment methods
    */
   private buildPaymentMethodsKey(userId: string): string {
-    return `${this.cacheConfigs.paymentMethods.prefix}:${userId}`;
+    return `${this.cacheConfigs["paymentMethods"]?.prefix}:${userId}`;
   }
 
   /**
@@ -528,7 +532,7 @@ export class WhmcsCacheService {
   async clearAllCache(): Promise<void> {
     try {
       const patterns = Object.values(this.cacheConfigs).map(config => `${config.prefix}:*`);
-      await Promise.all(patterns.map(pattern => this.cacheService.delPattern(pattern)));
+      await Promise.all(patterns.map(async pattern => this.cacheService.delPattern(pattern)));
       this.logger.warn("Cleared all WHMCS cache");
     } catch (error) {
       this.logger.error("Failed to clear all WHMCS cache", { error: extractErrorMessage(error) });

apps/bff/src/integrations/whmcs/connection/config/whmcs-config.service.ts

@@ -93,7 +93,7 @@ export class WhmcsConfigService {
     const value = this.configService.get<string>(key);
     if (!value) return defaultValue;
 
-    const parsed = parseInt(value, 10);
+    const parsed = Number.parseInt(value, 10);
-    return isNaN(parsed) ? defaultValue : parsed;
+    return Number.isNaN(parsed) ? defaultValue : parsed;
   }
 }

apps/bff/src/integrations/whmcs/connection/services/whmcs-connection-orchestrator.service.ts

@@ -26,8 +26,8 @@ import type {
   WhmcsUpdateInvoiceResponse,
   WhmcsCapturePaymentResponse,
 } from "@customer-portal/domain/billing/providers";
-import type { WhmcsGetPayMethodsParams } from "@customer-portal/domain/payments/providers";
 import type {
+  WhmcsGetPayMethodsParams,
   WhmcsPaymentMethodListResponse,
   WhmcsPaymentGatewayListResponse,
 } from "@customer-portal/domain/payments/providers";

apps/bff/src/integrations/whmcs/connection/services/whmcs-http-client.service.ts

@@ -128,7 +128,7 @@ export class WhmcsHttpClientService {
       if (!response.ok) {
         // Do NOT include response body in thrown error messages (could contain sensitive/PII and
         // would propagate into unified exception logs). If needed, emit a short snippet only in dev.
-        if (process.env.NODE_ENV !== "production") {
+        if (process.env["NODE_ENV"] !== "production") {
           const snippet = responseText?.slice(0, 300);
           if (snippet) {
             this.logger.debug(`WHMCS non-OK response body snippet [${action}]`, {
@@ -182,9 +182,9 @@ export class WhmcsHttpClientService {
 
   private appendFormParam(formData: URLSearchParams, key: string, value: unknown): void {
     if (Array.isArray(value)) {
-      value.forEach((entry, index) => {
+      for (const [index, entry] of value.entries()) {
         this.appendFormParam(formData, `${key}[${index}]`, entry);
-      });
+      }
       return;
     }
 
@@ -234,11 +234,11 @@ export class WhmcsHttpClientService {
     try {
       parsedResponse = JSON.parse(responseText);
     } catch (parseError) {
-      const isProd = process.env.NODE_ENV === "production";
+      const isProd = process.env["NODE_ENV"] === "production";
       this.logger.error(`Invalid JSON response from WHMCS API [${action}]`, {
         ...(isProd
           ? { responseTextLength: responseText.length }
-          : { responseText: responseText.substring(0, 500) }),
+          : { responseText: responseText.slice(0, 500) }),
         parseError: extractErrorMessage(parseError),
         params: redactForLogs(params),
       });
@@ -247,12 +247,12 @@ export class WhmcsHttpClientService {
 
     // Validate basic response structure
     if (!this.isWhmcsResponse(parsedResponse)) {
-      const isProd = process.env.NODE_ENV === "production";
+      const isProd = process.env["NODE_ENV"] === "production";
       this.logger.error(`WHMCS API returned invalid response structure [${action}]`, {
         responseType: typeof parsedResponse,
         ...(isProd
           ? { responseTextLength: responseText.length }
-          : { responseText: responseText.substring(0, 500) }),
+          : { responseText: responseText.slice(0, 500) }),
         params: redactForLogs(params),
       });
       throw new Error("Invalid response structure from WHMCS API");
@@ -308,7 +308,7 @@ export class WhmcsHttpClientService {
     }
 
     const record = value as Record<string, unknown>;
-    const rawResult = record.result;
+    const rawResult = record["result"];
     return rawResult === "success" || rawResult === "error";
   }
 

apps/bff/src/integrations/whmcs/connection/types/connection.types.ts

@@ -2,19 +2,19 @@ export interface WhmcsApiConfig {
   baseUrl: string;
   identifier: string;
   secret: string;
-  timeout?: number;
+  timeout?: number | undefined;
-  retryAttempts?: number;
+  retryAttempts?: number | undefined;
-  retryDelay?: number;
+  retryDelay?: number | undefined;
 }
 
 export interface WhmcsRequestOptions {
-  timeout?: number;
+  timeout?: number | undefined;
-  retryAttempts?: number;
+  retryAttempts?: number | undefined;
-  retryDelay?: number;
+  retryDelay?: number | undefined;
   /**
    * If true, the request will jump the queue and execute immediately
    */
-  highPriority?: boolean;
+  highPriority?: boolean | undefined;
 }
 
 export interface WhmcsRetryConfig {
@@ -29,6 +29,6 @@ export interface WhmcsConnectionStats {
   successfulRequests: number;
   failedRequests: number;
   averageResponseTime: number;
-  lastRequestTime?: Date;
+  lastRequestTime?: Date | undefined;
-  lastErrorTime?: Date;
+  lastErrorTime?: Date | undefined;
 }

apps/bff/src/integrations/whmcs/services/whmcs-currency.service.ts

@@ -114,13 +114,14 @@ export class WhmcsCurrencyService implements OnModuleInit, OnModuleDestroy {
       const response = (await this.connectionService.getCurrencies()) as WhmcsCurrenciesResponse;
 
       // Check if response has currencies data (success case) or error fields
-      if (response.result === "success" || (response.currencies && !response.error)) {
+      if (response.result === "success" || (response.currencies && !response["error"])) {
         // Parse the WHMCS response format into currency objects
         this.currencies = this.parseWhmcsCurrenciesResponse(response);
 
         if (this.currencies.length > 0) {
           // Set first currency as default (WHMCS typically returns the primary currency first)
-          this.defaultCurrency = this.currencies[0];
+          const firstCurrency = this.currencies[0];
+          this.defaultCurrency = firstCurrency ?? null;
 
           this.logger.log(`Loaded ${this.currencies.length} currencies from WHMCS`, {
             defaultCurrency: this.defaultCurrency?.code,
@@ -134,13 +135,13 @@ export class WhmcsCurrencyService implements OnModuleInit, OnModuleDestroy {
       } else {
         this.logger.error("WHMCS GetCurrencies returned error", {
           result: response?.result,
-          message: response?.message,
+          message: response?.["message"],
-          error: response?.error,
+          error: response?.["error"],
-          errorcode: response?.errorcode,
+          errorcode: response?.["errorcode"],
           fullResponse: JSON.stringify(response, null, 2),
         });
         throw new WhmcsOperationException(
-          `WHMCS GetCurrencies error: ${response?.message || response?.error || "Unknown error"}`,
+          `WHMCS GetCurrencies error: ${response?.["message"] || response?.["error"] || "Unknown error"}`,
           { operation: "getCurrencies" }
         );
       }
@@ -171,7 +172,7 @@ export class WhmcsCurrencyService implements OnModuleInit, OnModuleDestroy {
 
       for (const currencyData of currencyArray) {
         const currency: Currency = {
-          id: parseInt(String(currencyData.id)) || 0,
+          id: Number.parseInt(String(currencyData.id)) || 0,
           code: String(currencyData.code || ""),
           prefix: String(currencyData.prefix || ""),
           suffix: String(currencyData.suffix || ""),
@@ -194,14 +195,15 @@ export class WhmcsCurrencyService implements OnModuleInit, OnModuleDestroy {
       const currencyIndices = currencyKeys
         .map(key => {
           const match = key.match(/currencies\[currency\]\[(\d+)\]\[id\]/);
-          return match ? parseInt(match[1], 10) : null;
+          const indexStr = match?.[1];
+          return indexStr === undefined ? null : Number.parseInt(indexStr, 10);
         })
         .filter((index): index is number => index !== null);
 
       // Build currency objects from the flat response
       for (const index of currencyIndices) {
         const currency: Currency = {
-          id: parseInt(String(response[`currencies[currency][${index}][id]`])) || 0,
+          id: Number.parseInt(String(response[`currencies[currency][${index}][id]`])) || 0,
           code: String(response[`currencies[currency][${index}][code]`] || ""),
           prefix: String(response[`currencies[currency][${index}][prefix]`] || ""),
           suffix: String(response[`currencies[currency][${index}][suffix]`] || ""),

apps/bff/src/integrations/whmcs/services/whmcs-invoice.service.ts

@@ -14,8 +14,6 @@ import type {
   WhmcsCreateInvoiceParams,
   WhmcsUpdateInvoiceParams,
   WhmcsCapturePaymentParams,
-} from "@customer-portal/domain/billing/providers";
-import type {
   WhmcsInvoiceListResponse,
   WhmcsInvoiceResponse,
   WhmcsCreateInvoiceResponse,
@@ -66,7 +64,7 @@ export class WhmcsInvoiceService {
         limitnum: limit,
         orderby: "date",
         order: "DESC",
-        ...(status && { status: status as WhmcsGetInvoicesParams["status"] }),
+        ...(status ? { status: status as WhmcsGetInvoicesParams["status"] } : {}),
       };
 
       const response: WhmcsInvoiceListResponse = await this.connectionService.getInvoices(params);
@@ -118,6 +116,7 @@ export class WhmcsInvoiceService {
 
       for (let i = 0; i < batches.length; i++) {
         const batch = batches[i];
+        if (!batch) continue;
 
         // Process batch in parallel
         const batchResults = await Promise.all(
@@ -309,10 +308,10 @@ export class WhmcsInvoiceService {
         status: "Unpaid",
         sendnotification: false, // Don't send email notification automatically
         duedate: dueDateStr,
-        notes: params.notes,
         itemdescription1: params.description,
         itemamount1: params.amount,
         itemtaxed1: false, // No tax for data top-ups for now
+        ...(params.notes === undefined ? {} : { notes: params.notes }),
       };
 
       const response: WhmcsCreateInvoiceResponse =
@@ -372,9 +371,11 @@ export class WhmcsInvoiceService {
 
       const whmcsParams: WhmcsUpdateInvoiceParams = {
         invoiceid: params.invoiceId,
-        status: statusForUpdate,
+        ...(statusForUpdate === undefined ? {} : { status: statusForUpdate }),
-        duedate: params.dueDate ? params.dueDate.toISOString().split("T")[0] : undefined,
+        ...(params.dueDate === undefined
-        notes: params.notes,
+          ? {}
+          : { duedate: params.dueDate.toISOString().split("T")[0] }),
+        ...(params.notes === undefined ? {} : { notes: params.notes }),
       };
 
       const response: WhmcsUpdateInvoiceResponse =
@@ -394,7 +395,7 @@ export class WhmcsInvoiceService {
 
       return {
         success: true,
-        message: response.message,
+        ...(response.message === undefined ? {} : { message: response.message }),
       };
     } catch (error) {
       this.logger.error(`Failed to update invoice ${params.invoiceId}`, {
@@ -436,7 +437,9 @@ export class WhmcsInvoiceService {
 
         return {
           success: true,
-          transactionId: response.transactionid,
+          ...(response.transactionid === undefined
+            ? {}
+            : { transactionId: response.transactionid }),
         };
       } else {
         this.logger.warn(`Payment capture failed for invoice ${params.invoiceId}`, {

apps/bff/src/integrations/whmcs/services/whmcs-order.service.ts

@@ -10,8 +10,8 @@ import type {
   WhmcsAddOrderResponse,
   WhmcsOrderResult,
 } from "@customer-portal/domain/orders/providers";
-import { buildWhmcsAddOrderPayload } from "@customer-portal/domain/orders/providers";
 import {
+  buildWhmcsAddOrderPayload,
   whmcsAddOrderResponseSchema,
   whmcsAcceptOrderResponseSchema,
 } from "@customer-portal/domain/orders/providers";
@@ -47,14 +47,16 @@ export class WhmcsOrderService {
 
       this.logger.debug("Built WHMCS AddOrder payload", {
         clientId: params.clientId,
-        productCount: Array.isArray(addOrderPayload.pid) ? addOrderPayload.pid.length : 0,
+        productCount: Array.isArray(addOrderPayload["pid"])
-        pids: addOrderPayload.pid,
+          ? (addOrderPayload["pid"] as unknown[]).length
-        quantities: addOrderPayload.qty, // CRITICAL: Must be included for products to be added
+          : 0,
-        billingCycles: addOrderPayload.billingcycle,
+        pids: addOrderPayload["pid"],
-        hasConfigOptions: Boolean(addOrderPayload.configoptions),
+        quantities: addOrderPayload["qty"], // CRITICAL: Must be included for products to be added
-        hasCustomFields: Boolean(addOrderPayload.customfields),
+        billingCycles: addOrderPayload["billingcycle"],
-        promoCode: addOrderPayload.promocode,
+        hasConfigOptions: Boolean(addOrderPayload["configoptions"]),
-        paymentMethod: addOrderPayload.paymentmethod,
+        hasCustomFields: Boolean(addOrderPayload["customfields"]),
+        promoCode: addOrderPayload["promocode"],
+        paymentMethod: addOrderPayload["paymentmethod"],
       });
 
       // Call WHMCS AddOrder API
@@ -104,7 +106,7 @@ export class WhmcsOrderService {
         sfOrderId: params.sfOrderId,
         itemCount: params.items.length,
         // Include first 100 chars of error stack for debugging
-        errorStack: error instanceof Error ? error.stack?.substring(0, 100) : undefined,
+        errorStack: error instanceof Error ? error.stack?.slice(0, 100) : undefined,
       });
       throw error;
     }
@@ -163,7 +165,7 @@ export class WhmcsOrderService {
         orderId,
         sfOrderId,
         // Include first 100 chars of error stack for debugging
-        errorStack: error instanceof Error ? error.stack?.substring(0, 100) : undefined,
+        errorStack: error instanceof Error ? error.stack?.slice(0, 100) : undefined,
       });
       throw error;
     }
@@ -179,7 +181,8 @@ export class WhmcsOrderService {
         id: orderId.toString(),
       })) as Record<string, unknown>;
 
-      return (response.orders as { order?: Record<string, unknown>[] })?.order?.[0] || null;
+      const orders = response["orders"] as { order?: Record<string, unknown>[] } | undefined;
+      return orders?.order?.[0] ?? null;
     } catch (error) {
       this.logger.error("Failed to get WHMCS order details", {
         error: extractErrorMessage(error),
@@ -231,17 +234,17 @@ export class WhmcsOrderService {
     this.logger.debug("Built WHMCS AddOrder payload", {
       clientId: params.clientId,
       productCount: params.items.length,
-      pids: payload.pid,
+      pids: payload["pid"],
-      billingCycles: payload.billingcycle,
+      billingCycles: payload["billingcycle"],
-      hasConfigOptions: !!payload.configoptions,
+      hasConfigOptions: !!payload["configoptions"],
-      hasCustomFields: !!payload.customfields,
+      hasCustomFields: !!payload["customfields"],
     });
 
     return payload as Record<string, unknown>;
   }
 
   private toWhmcsOrderResult(response: WhmcsAddOrderResponse): WhmcsOrderResult {
-    const orderId = parseInt(String(response.orderid), 10);
+    const orderId = Number.parseInt(String(response.orderid), 10);
     if (!orderId || Number.isNaN(orderId)) {
       throw new WhmcsOperationException("WHMCS AddOrder did not return valid order ID", {
         response,
@@ -250,7 +253,7 @@ export class WhmcsOrderService {
 
     return {
       orderId,
-      invoiceId: response.invoiceid ? parseInt(String(response.invoiceid), 10) : undefined,
+      invoiceId: response.invoiceid ? Number.parseInt(String(response.invoiceid), 10) : undefined,
       serviceIds: this.parseDelimitedIds(response.serviceids),
       addonIds: this.parseDelimitedIds(response.addonids),
       domainIds: this.parseDelimitedIds(response.domainids),
@@ -264,7 +267,7 @@ export class WhmcsOrderService {
     return value
       .toString()
       .split(",")
-      .map(entry => parseInt(entry.trim(), 10))
+      .map(entry => Number.parseInt(entry.trim(), 10))
       .filter(id => !Number.isNaN(id));
   }
 }

apps/bff/src/integrations/whmcs/services/whmcs-payment.service.ts

@@ -16,8 +16,8 @@ import { transformWhmcsCatalogProductsResponse } from "@customer-portal/domain/s
 import { WhmcsConnectionOrchestratorService } from "../connection/services/whmcs-connection-orchestrator.service.js";
 import { WhmcsCacheService } from "../cache/whmcs-cache.service.js";
 import type { WhmcsCreateSsoTokenParams } from "@customer-portal/domain/customer/providers";
-import type { WhmcsGetPayMethodsParams } from "@customer-portal/domain/payments/providers";
 import type {
+  WhmcsGetPayMethodsParams,
   WhmcsPaymentMethod,
   WhmcsPaymentMethodListResponse,
   WhmcsPaymentGateway,
@@ -270,7 +270,7 @@ export class WhmcsPaymentService {
    * Debug helper: log only the host of the SSO URL (never the token) in non-production.
    */
   private debugLogRedirectHost(url: string): void {
-    if (process.env.NODE_ENV === "production") return;
+    if (process.env["NODE_ENV"] === "production") return;
     try {
       const target = new URL(url);
       const base = new URL(this.connectionService.getBaseUrl());

apps/bff/src/integrations/whmcs/services/whmcs-sso.service.ts

@@ -207,7 +207,7 @@ export class WhmcsSsoService {
    * Debug helper: log only the host of the SSO URL (never the token) in non-production.
    */
   private debugLogRedirectHost(url: string): void {
-    if (process.env.NODE_ENV === "production") return;
+    if (process.env["NODE_ENV"] === "production") return;
     try {
       const target = new URL(url);
       const base = new URL(this.connectionService.getBaseUrl());

apps/bff/src/main.ts

@@ -15,7 +15,6 @@ for (const signal of signals) {
       if (!app) {
         logger.warn("Nest application not initialized. Exiting immediately.");
         process.exit(0);
-        return;
       }
 
       try {

apps/bff/src/modules/auth/application/auth.facade.ts

@@ -109,15 +109,14 @@ export class AuthFacade {
 
     const profile = mapPrismaUserToDomain(prismaUser);
 
+    const userAgent = request?.headers?.["user-agent"];
     const tokens = await this.tokenService.generateTokenPair(
       {
         id: profile.id,
         email: profile.email,
         role: prismaUser.role || "USER",
       },
-      {
+      userAgent ? { userAgent } : {}
-        userAgent: request?.headers["user-agent"],
-      }
     );
 
     await this.updateAccountLastSignIn(user.id);
@@ -290,7 +289,7 @@ export class AuthFacade {
 
   async refreshTokens(
     refreshToken: string | undefined,
-    deviceInfo?: { deviceId?: string; userAgent?: string }
+    deviceInfo?: { deviceId?: string | undefined; userAgent?: string | undefined }
   ) {
     if (!refreshToken) {
       throw new UnauthorizedException("Invalid refresh token");

apps/bff/src/modules/auth/auth.types.ts

@@ -1,7 +1,6 @@
-import type { User } from "@customer-portal/domain/customer";
+import type { User, UserAuth } from "@customer-portal/domain/customer";
 import type { Request } from "express";
 import type { AuthTokens } from "@customer-portal/domain/auth";
-import type { UserAuth } from "@customer-portal/domain/customer";
 
 export type RequestWithUser = Request & { user: User };
 

apps/bff/src/modules/auth/infra/otp/get-started-session.service.ts

@@ -11,6 +11,7 @@ import type {
 } from "@customer-portal/domain/get-started";
 
 import { CacheService } from "@/infra/cache/cache.service.js";
+import { DistributedLockService } from "@/infra/cache/distributed-lock.service.js";
 
 /**
  * Session data stored in Redis (internal representation)
@@ -18,6 +19,10 @@ import { CacheService } from "@/infra/cache/cache.service.js";
 interface SessionData extends Omit<GetStartedSession, "expiresAt"> {
   /** Session ID (for lookup) */
   id: string;
+  /** Timestamp when session was marked as used (for one-time operations) */
+  usedAt?: string;
+  /** The operation that used this session */
+  usedFor?: "guest_eligibility" | "signup_with_eligibility" | "complete_account";
 }
 
 /**
@@ -36,11 +41,13 @@ interface SessionData extends Omit<GetStartedSession, "expiresAt"> {
 export class GetStartedSessionService {
   private readonly SESSION_PREFIX = "get-started-session:";
   private readonly HANDOFF_PREFIX = "guest-handoff:";
+  private readonly SESSION_LOCK_PREFIX = "session-lock:";
   private readonly ttlSeconds: number;
   private readonly handoffTtlSeconds = 1800; // 30 minutes for handoff tokens
 
   constructor(
     private readonly cache: CacheService,
+    private readonly lockService: DistributedLockService,
     private readonly config: ConfigService,
     @Inject(Logger) private readonly logger: Logger
   ) {
@@ -277,6 +284,148 @@ export class GetStartedSessionService {
     this.logger.debug({ tokenId: token }, "Guest handoff token invalidated");
   }
 
+  // ============================================================================
+  // Session Locking (Idempotency Protection)
+  // ============================================================================
+
+  /**
+   * Atomically acquire a lock and mark the session as used for a specific operation.
+   *
+   * This prevents race conditions where the same session could be used
+   * multiple times (e.g., double-clicking "Create Account").
+   *
+   * @param sessionToken - Session token
+   * @param operation - The operation being performed
+   * @returns Object with success flag and session data if acquired
+   */
+  async acquireAndMarkAsUsed(
+    sessionToken: string,
+    operation: SessionData["usedFor"]
+  ): Promise<{ success: true; session: GetStartedSession } | { success: false; reason: string }> {
+    const lockKey = `${this.SESSION_LOCK_PREFIX}${sessionToken}`;
+
+    // Try to acquire lock with no retries (immediate fail if already locked)
+    const lockResult = await this.lockService.tryWithLock(
+      lockKey,
+      async () => {
+        // Check session state within lock
+        const sessionData = await this.cache.get<SessionData>(this.buildKey(sessionToken));
+
+        if (!sessionData) {
+          return { success: false as const, reason: "Session not found or expired" };
+        }
+
+        if (!sessionData.emailVerified) {
+          return { success: false as const, reason: "Session email not verified" };
+        }
+
+        if (sessionData.usedAt) {
+          this.logger.warn(
+            { sessionId: sessionToken, usedFor: sessionData.usedFor, usedAt: sessionData.usedAt },
+            "Session already used"
+          );
+          return {
+            success: false as const,
+            reason: `Session already used for ${sessionData.usedFor}`,
+          };
+        }
+
+        // Mark as used - build object with required fields, then add optional fields
+        const updatedData = Object.assign(
+          {
+            id: sessionData.id,
+            email: sessionData.email,
+            emailVerified: sessionData.emailVerified,
+            createdAt: sessionData.createdAt,
+            usedAt: new Date().toISOString(),
+            usedFor: operation,
+          },
+          sessionData.accountStatus ? { accountStatus: sessionData.accountStatus } : {},
+          sessionData.firstName ? { firstName: sessionData.firstName } : {},
+          sessionData.lastName ? { lastName: sessionData.lastName } : {},
+          sessionData.phone ? { phone: sessionData.phone } : {},
+          sessionData.address ? { address: sessionData.address } : {},
+          sessionData.sfAccountId ? { sfAccountId: sessionData.sfAccountId } : {},
+          sessionData.whmcsClientId === undefined
+            ? {}
+            : { whmcsClientId: sessionData.whmcsClientId },
+          sessionData.eligibilityStatus ? { eligibilityStatus: sessionData.eligibilityStatus } : {}
+        ) as SessionData;
+
+        const remainingTtl = this.calculateRemainingTtl(sessionData.createdAt);
+        await this.cache.set(this.buildKey(sessionToken), updatedData, remainingTtl);
+
+        this.logger.debug({ sessionId: sessionToken, operation }, "Session marked as used");
+
+        return {
+          success: true as const,
+          session: {
+            ...updatedData,
+            expiresAt: this.calculateExpiresAt(sessionData.createdAt),
+          },
+        };
+      },
+      { ttlMs: 65_000, maxRetries: 0 } // TTL must exceed workflow lock (60s) - fail fast
+    );
+
+    if (!lockResult.success) {
+      this.logger.warn(
+        { sessionId: sessionToken },
+        "Failed to acquire session lock - operation in progress"
+      );
+      return { success: false, reason: "Operation already in progress" };
+    }
+
+    return lockResult.result;
+  }
+
+  /**
+   * Check if a session has already been used for an operation
+   */
+  async isSessionUsed(sessionToken: string): Promise<boolean> {
+    const sessionData = await this.cache.get<SessionData>(this.buildKey(sessionToken));
+    return sessionData?.usedAt != null;
+  }
+
+  /**
+   * Clear the "used" status from a session (for recovery after partial failure)
+   *
+   * This should only be called when rolling back a failed operation
+   * to allow the user to retry.
+   */
+  async clearUsedStatus(sessionToken: string): Promise<boolean> {
+    const sessionData = await this.cache.get<SessionData>(this.buildKey(sessionToken));
+
+    if (!sessionData) {
+      return false;
+    }
+
+    // Build clean session data without usedAt and usedFor
+    const cleanSessionData = Object.assign(
+      {
+        id: sessionData.id,
+        email: sessionData.email,
+        emailVerified: sessionData.emailVerified,
+        createdAt: sessionData.createdAt,
+      },
+      sessionData.accountStatus ? { accountStatus: sessionData.accountStatus } : {},
+      sessionData.firstName ? { firstName: sessionData.firstName } : {},
+      sessionData.lastName ? { lastName: sessionData.lastName } : {},
+      sessionData.phone ? { phone: sessionData.phone } : {},
+      sessionData.address ? { address: sessionData.address } : {},
+      sessionData.sfAccountId ? { sfAccountId: sessionData.sfAccountId } : {},
+      sessionData.whmcsClientId === undefined ? {} : { whmcsClientId: sessionData.whmcsClientId },
+      sessionData.eligibilityStatus ? { eligibilityStatus: sessionData.eligibilityStatus } : {}
+    ) as SessionData;
+
+    const remainingTtl = this.calculateRemainingTtl(sessionData.createdAt);
+    await this.cache.set(this.buildKey(sessionToken), cleanSessionData, remainingTtl);
+
+    this.logger.debug({ sessionId: sessionToken }, "Session used status cleared for retry");
+
+    return true;
+  }
+
   private buildKey(sessionId: string): string {
     return `${this.SESSION_PREFIX}${sessionId}`;
   }

apps/bff/src/modules/auth/infra/otp/otp.service.ts

@@ -17,7 +17,7 @@ interface OtpData {
   /** When the code was created */
   createdAt: string;
   /** Optional fingerprint binding (SHA256 hash of IP + User-Agent) */
-  fingerprint?: string;
+  fingerprint?: string | undefined;
 }
 
 /**

apps/bff/src/modules/auth/infra/rate-limiting/auth-rate-limit.service.ts

@@ -133,7 +133,6 @@ export class AuthRateLimitService {
         points: limit,
         duration,
         inMemoryBlockOnConsumed: limit + 1,
-        insuranceLimiter: undefined,
       });
     } catch (error: unknown) {
       this.logger.error(

apps/bff/src/modules/auth/infra/token/jose-jwt.service.ts

@@ -7,10 +7,10 @@ import { parseJwtExpiry } from "../../utils/jwt-expiry.util.js";
 export class JoseJwtService {
   private readonly signingKey: Uint8Array;
   private readonly verificationKeys: Uint8Array[];
-  private readonly issuer?: string;
+  private readonly issuer: string | undefined;
-  private readonly audience?: string | string[];
+  private readonly audience: string | string[] | undefined;
 
-  constructor(private readonly configService: ConfigService) {
+  constructor(configService: ConfigService) {
     const secret = configService.get<string>("JWT_SECRET");
     if (!secret) {
       throw new Error("JWT_SECRET is required in environment variables");
@@ -83,15 +83,16 @@ export class JoseJwtService {
 
   async verify<T extends JWTPayload>(token: string): Promise<T> {
     const options = {
-      algorithms: ["HS256"],
+      algorithms: ["HS256"] as string[],
-      issuer: this.issuer,
+      ...(this.issuer === undefined ? {} : { issuer: this.issuer }),
-      audience: this.audience,
+      ...(this.audience === undefined ? {} : { audience: this.audience }),
     };
 
     let lastError: unknown;
 
     for (let i = 0; i < this.verificationKeys.length; i++) {
       const key = this.verificationKeys[i];
+      if (!key) continue;
       try {
         const { payload } = await jwtVerify(token, key, options);
         return payload as T;

apps/bff/src/modules/auth/infra/token/token-migration.service.ts

@@ -1,6 +1,5 @@
 import { Injectable, Inject } from "@nestjs/common";
 import { Logger } from "nestjs-pino";
-import { ConfigService } from "@nestjs/config";
 import { Redis } from "ioredis";
 import { extractErrorMessage } from "@bff/core/utils/error.util.js";
 
@@ -32,8 +31,7 @@ export class TokenMigrationService {
 
   constructor(
     @Inject("REDIS_CLIENT") private readonly redis: Redis,
-    @Inject(Logger) private readonly logger: Logger,
+    @Inject(Logger) private readonly logger: Logger
-    private readonly configService: ConfigService
   ) {}
 
   /**
@@ -415,7 +413,7 @@ export class TokenMigrationService {
     }
 
     const record = parsed as Record<string, unknown>;
-    const userId = record.userId;
+    const userId = record["userId"];
 
     if (typeof userId !== "string" || userId.length === 0) {
       this.logger.warn("Invalid family structure, skipping", { familyKey });
@@ -448,8 +446,8 @@ export class TokenMigrationService {
     }
 
     const record = parsed as Record<string, unknown>;
-    const userId = record.userId;
+    const userId = record["userId"];
-    const familyId = record.familyId;
+    const familyId = record["familyId"];
 
     if (typeof userId !== "string" || typeof familyId !== "string") {
       this.logger.warn("Invalid token structure, skipping", { tokenKey });

apps/bff/src/modules/auth/infra/token/token-revocation.service.ts

@@ -145,19 +145,22 @@ export class TokenRevocationService {
   /**
    * Get all active refresh token families for a user
    */
-  async getUserRefreshTokenFamilies(
+  async getUserRefreshTokenFamilies(userId: string): Promise<
-    userId: string
+    Array<{
-  ): Promise<
+      familyId: string;
-    Array<{ familyId: string; deviceId?: string; userAgent?: string; createdAt?: string }>
+      deviceId?: string | undefined;
+      userAgent?: string | undefined;
+      createdAt?: string | undefined;
+    }>
   > {
     try {
       const familyIds = await this.storage.getUserFamilyIds(userId);
 
       const families: Array<{
         familyId: string;
-        deviceId?: string;
+        deviceId?: string | undefined;
-        userAgent?: string;
+        userAgent?: string | undefined;
-        createdAt?: string;
+        createdAt?: string | undefined;
       }> = [];
 
       for (const familyId of familyIds) {

apps/bff/src/modules/auth/infra/token/token-storage.service.ts

@@ -11,10 +11,10 @@ export interface StoredRefreshToken {
 export interface StoredRefreshTokenFamily {
   userId: string;
   tokenHash: string;
-  deviceId?: string;
+  deviceId?: string | undefined;
-  userAgent?: string;
+  userAgent?: string | undefined;
-  createdAt?: string;
+  createdAt?: string | undefined;
-  absoluteExpiresAt?: string;
+  absoluteExpiresAt?: string | undefined;
 }
 
 /**
@@ -41,7 +41,7 @@ export class TokenStorageService {
     userId: string,
     familyId: string,
     refreshTokenHash: string,
-    deviceInfo?: { deviceId?: string; userAgent?: string },
+    deviceInfo?: { deviceId?: string | undefined; userAgent?: string | undefined },
     refreshExpirySeconds?: number,
     absoluteExpiresAt?: string
   ): Promise<void> {
@@ -86,7 +86,7 @@ export class TokenStorageService {
     const results = await pipeline.exec();
 
     // Check if user has too many tokens
-    const cardResult = results?.[results.length - 1];
+    const cardResult = results?.at(-1);
     if (
       cardResult &&
       Array.isArray(cardResult) &&
@@ -155,7 +155,7 @@ export class TokenStorageService {
     familyId: string,
     userId: string,
     newTokenHash: string,
-    deviceInfo: { deviceId?: string; userAgent?: string } | undefined,
+    deviceInfo: { deviceId?: string | undefined; userAgent?: string | undefined } | undefined,
     createdAt: string,
     absoluteExpiresAt: string,
     ttlSeconds: number

apps/bff/src/modules/auth/infra/token/token.service.ts

@@ -23,14 +23,14 @@ export interface RefreshTokenPayload extends JWTPayload {
    * Refresh token family identifier (stable across rotations).
    * Present on newly issued tokens; legacy tokens used `tokenId` for this value.
    */
-  familyId?: string;
+  familyId?: string | undefined;
   /**
    * Refresh token identifier (unique per token). Used for replay/reuse detection.
    * For legacy tokens, this was equal to the family id.
    */
   tokenId: string;
-  deviceId?: string;
+  deviceId?: string | undefined;
-  userAgent?: string;
+  userAgent?: string | undefined;
   type: "refresh";
 }
 
@@ -201,8 +201,8 @@ export class AuthTokenService {
   async refreshTokens(
     refreshToken: string,
     deviceInfo?: {
-      deviceId?: string;
+      deviceId?: string | undefined;
-      userAgent?: string;
+      userAgent?: string | undefined;
     }
   ): Promise<{ tokens: AuthTokens; user: User }> {
     if (!refreshToken) {
@@ -297,10 +297,10 @@ export class AuthTokenService {
 
       if (absoluteExpiresAt) {
         const absMs = Date.parse(absoluteExpiresAt);
-        if (!Number.isNaN(absMs)) {
+        if (Number.isNaN(absMs)) {
-          remainingSeconds = Math.max(0, Math.floor((absMs - Date.now()) / 1000));
-        } else {
           absoluteExpiresAt = undefined;
+        } else {
+          remainingSeconds = Math.max(0, Math.floor((absMs - Date.now()) / 1000));
         }
       }
 
@@ -426,10 +426,13 @@ export class AuthTokenService {
   /**
    * Get all active refresh token families for a user
    */
-  async getUserRefreshTokenFamilies(
+  async getUserRefreshTokenFamilies(userId: string): Promise<
-    userId: string
+    Array<{
-  ): Promise<
+      familyId: string;
-    Array<{ familyId: string; deviceId?: string; userAgent?: string; createdAt?: string }>
+      deviceId?: string | undefined;
+      userAgent?: string | undefined;
+      createdAt?: string | undefined;
+    }>
   > {
     return this.revocation.getUserRefreshTokenFamilies(userId);
   }
@@ -451,7 +454,7 @@ export class AuthTokenService {
 
   private parseExpiryToMs(expiry: string): number {
     const unit = expiry.slice(-1);
-    const value = parseInt(expiry.slice(0, -1));
+    const value = Number.parseInt(expiry.slice(0, -1));
 
     switch (unit) {
       case "s":

apps/bff/src/modules/auth/infra/workflows/get-started-workflow.service.ts

@@ -3,6 +3,8 @@ import { ConfigService } from "@nestjs/config";
 import { Logger } from "nestjs-pino";
 import * as argon2 from "argon2";
 
+import { DistributedLockService } from "@bff/infra/cache/distributed-lock.service.js";
+
 import {
   ACCOUNT_STATUS,
   type AccountStatus,
@@ -17,6 +19,7 @@ import {
   type CompleteAccountRequest,
   type MaybeLaterRequest,
   type MaybeLaterResponse,
+  type SignupWithEligibilityRequest,
 } from "@customer-portal/domain/get-started";
 
 import { EmailService } from "@bff/infra/email/email.service.js";
@@ -43,6 +46,15 @@ import {
 } from "@bff/modules/auth/constants/portal.constants.js";
 import { SalesforceService } from "@bff/integrations/salesforce/salesforce.service.js";
 
+/**
+ * Remove undefined properties from an object (for exactOptionalPropertyTypes compatibility)
+ */
+function removeUndefined<T extends Record<string, unknown>>(obj: T): Partial<T> {
+  return Object.fromEntries(
+    Object.entries(obj).filter(([, value]) => value !== undefined)
+  ) as Partial<T>;
+}
+
 /**
  * Get Started Workflow Service
  *
@@ -70,6 +82,7 @@ export class GetStartedWorkflowService {
     private readonly whmcsSignup: SignupWhmcsService,
     private readonly userCreation: SignupUserCreationService,
     private readonly tokenService: AuthTokenService,
+    private readonly lockService: DistributedLockService,
     @Inject(Logger) private readonly logger: Logger
   ) {}
 
@@ -155,15 +168,23 @@ export class GetStartedWorkflowService {
     const prefill = this.getPrefillData(normalizedEmail, accountStatus);
 
     // Update session with verified status and account info
-    await this.sessionService.markEmailVerified(sessionToken, accountStatus.status, {
+    // Build prefill data object without undefined values (exactOptionalPropertyTypes)
-      firstName: prefill?.firstName,
+    const prefillData = {
-      lastName: prefill?.lastName,
+      ...(prefill?.firstName && { firstName: prefill.firstName }),
-      phone: prefill?.phone,
+      ...(prefill?.lastName && { lastName: prefill.lastName }),
-      address: prefill?.address,
+      ...(prefill?.phone && { phone: prefill.phone }),
-      sfAccountId: accountStatus.sfAccountId,
+      ...(prefill?.address && { address: prefill.address }),
+      ...(accountStatus.sfAccountId && { sfAccountId: accountStatus.sfAccountId }),
+      ...(accountStatus.whmcsClientId !== undefined && {
         whmcsClientId: accountStatus.whmcsClientId,
-      eligibilityStatus: prefill?.eligibilityStatus,
+      }),
-    });
+      ...(prefill?.eligibilityStatus && { eligibilityStatus: prefill.eligibilityStatus }),
+    };
+    await this.sessionService.markEmailVerified(
+      sessionToken,
+      accountStatus.status,
+      Object.keys(prefillData).length > 0 ? prefillData : undefined
+    );
 
     this.logger.log(
       { email: normalizedEmail, accountStatus: accountStatus.status },
@@ -221,13 +242,13 @@ export class GetStartedWorkflowService {
       // Create eligibility case
       const requestId = await this.createEligibilityCase(sfAccountId, address);
 
-      // Update session with SF account info
+      // Update session with SF account info (clean address to remove undefined values)
       await this.sessionService.updateWithQuickCheckData(request.sessionToken, {
         firstName,
         lastName,
-        address,
+        address: removeUndefined(address),
-        phone,
+        ...(phone && { phone }),
-        sfAccountId,
+        ...(sfAccountId && { sfAccountId }),
       });
 
       return {
@@ -286,6 +307,9 @@ export class GetStartedWorkflowService {
    * Creates SF Account + eligibility case immediately.
    * Email verification happens later when user creates an account.
    *
+   * Security:
+   * - Email-level lock prevents concurrent requests creating duplicate SF accounts
+   *
    * @param request - Guest eligibility request with name, email, address
    * @param fingerprint - Request fingerprint for logging/abuse detection
    */
@@ -301,7 +325,13 @@ export class GetStartedWorkflowService {
       "Guest eligibility check initiated"
     );
 
+    // Email-level lock to prevent concurrent requests for the same email
+    const lockKey = `guest-eligibility:${normalizedEmail}`;
+
     try {
+      return await this.lockService.withLock(
+        lockKey,
+        async () => {
           // Check if SF account already exists for this email
           let sfAccountId: string;
 
@@ -340,8 +370,8 @@ export class GetStartedWorkflowService {
             handoffToken = await this.sessionService.createGuestHandoffToken(normalizedEmail, {
               firstName,
               lastName,
-          address,
+              address: removeUndefined(address),
-          phone,
+              ...(phone && { phone }),
               sfAccountId,
             });
             this.logger.debug(
@@ -360,6 +390,9 @@ export class GetStartedWorkflowService {
             handoffToken,
             message: "Eligibility check submitted. We'll notify you of the results.",
           };
+        },
+        { ttlMs: 30_000 } // 30 second lock timeout
+      );
     } catch (error) {
       this.logger.error(
         { error: extractErrorMessage(error), email: normalizedEmail },
@@ -380,19 +413,35 @@ export class GetStartedWorkflowService {
   /**
    * Complete account for users with SF account but no WHMCS/Portal
    * Creates WHMCS client and Portal user, links to existing SF account
+   *
+   * Security:
+   * - Session is locked to prevent double submissions
+   * - Email-level lock prevents concurrent account creation
    */
   async completeAccount(request: CompleteAccountRequest): Promise<AuthResultInternal> {
-    const session = await this.sessionService.validateVerifiedSession(request.sessionToken);
+    // Atomically acquire session lock and mark as used
-    if (!session) {
+    const sessionResult = await this.sessionService.acquireAndMarkAsUsed(
-      throw new BadRequestException("Invalid or expired session. Please verify your email again.");
+      request.sessionToken,
+      "complete_account"
+    );
+
+    if (!sessionResult.success) {
+      throw new BadRequestException(sessionResult.reason);
     }
 
+    const session = sessionResult.session;
+
     if (!session.sfAccountId) {
       throw new BadRequestException("No Salesforce account found. Please check eligibility first.");
     }
 
     const { password, phone, dateOfBirth, gender } = request;
+    const lockKey = `complete-account:${session.email}`;
 
+    try {
+      return await this.lockService.withLock(
+        lockKey,
+        async () => {
           // Verify SF account still exists
           const existingSf = await this.salesforceAccountService.findByEmail(session.email);
           if (!existingSf || existingSf.id !== session.sfAccountId) {
@@ -415,7 +464,6 @@ export class GetStartedWorkflowService {
 
           const passwordHash = await argon2.hash(password);
 
-    try {
           // Get address from session or SF
           const address = session.address;
           if (!address || !address.address1 || !address.city || !address.postcode) {
@@ -431,7 +479,7 @@ export class GetStartedWorkflowService {
             phone,
             address: {
               address1: address.address1,
-          address2: address.address2 ?? undefined,
+              ...(address.address2 && { address2: address.address2 }),
               city: address.city,
               state: address.state ?? "",
               postcode: address.postcode,
@@ -471,7 +519,7 @@ export class GetStartedWorkflowService {
           // Update Salesforce portal flags
           await this.updateSalesforcePortalFlags(session.sfAccountId, whmcsClient.clientId);
 
-      // Invalidate session
+          // Invalidate session (fully done)
           await this.sessionService.invalidate(request.sessionToken);
 
           this.logger.log(
@@ -483,15 +531,216 @@ export class GetStartedWorkflowService {
             user: profile,
             tokens,
           };
+        },
+        { ttlMs: 60_000 }
+      );
     } catch (error) {
       this.logger.error(
         { error: extractErrorMessage(error), email: session.email },
         "Account completion failed"
       );
+
+      // Don't clear usedStatus on error - partial resources may have been created.
+      // The user must verify their email again to start fresh.
+
       throw error;
     }
   }
 
+  // ============================================================================
+  // Full Signup with Eligibility (Inline Flow)
+  // ============================================================================
+
+  /**
+   * Full signup with eligibility check - creates everything in one operation
+   *
+   * This is the primary signup path from the eligibility check page.
+   * Creates SF Account + Case + WHMCS + Portal after email verification.
+   *
+   * Security:
+   * - Session is locked to prevent double submissions (race condition protection)
+   * - Email-level lock prevents concurrent signups for the same email
+   * - Session is invalidated on success, cleared on partial failure for retry
+   *
+   * @param request - Signup request with all required data
+   */
+  async signupWithEligibility(request: SignupWithEligibilityRequest): Promise<{
+    success: boolean;
+    message?: string;
+    eligibilityRequestId?: string;
+    authResult?: AuthResultInternal;
+  }> {
+    // Atomically acquire session lock and mark as used
+    const sessionResult = await this.sessionService.acquireAndMarkAsUsed(
+      request.sessionToken,
+      "signup_with_eligibility"
+    );
+
+    if (!sessionResult.success) {
+      return {
+        success: false,
+        message: sessionResult.reason,
+      };
+    }
+
+    const session = sessionResult.session;
+    const { firstName, lastName, address, phone, password, dateOfBirth, gender } = request;
+    const normalizedEmail = session.email;
+
+    this.logger.log({ email: normalizedEmail }, "Starting signup with eligibility");
+
+    // Email-level lock to prevent concurrent signups for the same email
+    const lockKey = `signup-email:${normalizedEmail}`;
+
+    try {
+      return await this.lockService.withLock(
+        lockKey,
+        async () => {
+          // Check for existing Portal user
+          const existingPortalUser = await this.usersFacade.findByEmailInternal(normalizedEmail);
+          if (existingPortalUser) {
+            return {
+              success: false,
+              message: "An account already exists with this email. Please log in.",
+            };
+          }
+
+          // Check for existing WHMCS client
+          const existingWhmcs = await this.whmcsDiscovery.findClientByEmail(normalizedEmail);
+          if (existingWhmcs) {
+            return {
+              success: false,
+              message:
+                "A billing account already exists with this email. Please use account linking instead.",
+            };
+          }
+
+          // Check for existing SF Account or create new one
+          let sfAccountId: string;
+          let customerNumber: string | undefined;
+
+          const existingSf = await this.salesforceAccountService.findByEmail(normalizedEmail);
+          if (existingSf) {
+            sfAccountId = existingSf.id;
+            customerNumber = existingSf.accountNumber;
+            this.logger.log(
+              { email: normalizedEmail, sfAccountId },
+              "Using existing SF account for signup"
+            );
+          } else {
+            // Create new SF Account
+            const { accountId, accountNumber } = await this.salesforceAccountService.createAccount({
+              firstName,
+              lastName,
+              email: normalizedEmail,
+              phone: phone ?? "",
+            });
+            sfAccountId = accountId;
+            customerNumber = accountNumber;
+            this.logger.log(
+              { email: normalizedEmail, sfAccountId },
+              "Created new SF account for signup"
+            );
+          }
+
+          // Create eligibility case
+          const eligibilityRequestId = await this.createEligibilityCase(sfAccountId, address);
+
+          // Hash password
+          const passwordHash = await argon2.hash(password);
+
+          // Create WHMCS client
+          const whmcsClient = await this.whmcsSignup.createClient({
+            firstName,
+            lastName,
+            email: normalizedEmail,
+            password,
+            phone,
+            address: {
+              address1: address.address1,
+              ...(address.address2 && { address2: address.address2 }),
+              city: address.city,
+              state: address.state ?? "",
+              postcode: address.postcode,
+              country: address.country ?? "Japan",
+            },
+            customerNumber,
+            dateOfBirth,
+            gender,
+          });
+
+          // Create Portal user and mapping
+          const { userId } = await this.userCreation.createUserWithMapping({
+            email: normalizedEmail,
+            passwordHash,
+            whmcsClientId: whmcsClient.clientId,
+            sfAccountId,
+          });
+
+          // Fetch fresh user and generate tokens
+          const freshUser = await this.usersFacade.findByIdInternal(userId);
+          if (!freshUser) {
+            throw new Error("Failed to load created user");
+          }
+
+          await this.auditService.logAuthEvent(AuditAction.SIGNUP, userId, {
+            email: normalizedEmail,
+            whmcsClientId: whmcsClient.clientId,
+            source: "signup_with_eligibility",
+          });
+
+          const profile = mapPrismaUserToDomain(freshUser);
+          const tokens = await this.tokenService.generateTokenPair({
+            id: profile.id,
+            email: profile.email,
+          });
+
+          // Update Salesforce portal flags
+          await this.updateSalesforcePortalFlags(sfAccountId, whmcsClient.clientId);
+
+          // Invalidate session (fully done, no retry needed)
+          await this.sessionService.invalidate(request.sessionToken);
+
+          // Send welcome email (includes eligibility info)
+          await this.sendWelcomeWithEligibilityEmail(
+            normalizedEmail,
+            firstName,
+            eligibilityRequestId
+          );
+
+          this.logger.log(
+            { email: normalizedEmail, userId, eligibilityRequestId },
+            "Signup with eligibility completed successfully"
+          );
+
+          return {
+            success: true,
+            eligibilityRequestId,
+            authResult: {
+              user: profile,
+              tokens,
+            },
+          };
+        },
+        { ttlMs: 60_000 } // 60 second lock timeout for the full operation
+      );
+    } catch (error) {
+      this.logger.error(
+        { error: extractErrorMessage(error), email: normalizedEmail },
+        "Signup with eligibility failed"
+      );
+
+      // Don't clear usedStatus on error - partial resources may have been created.
+      // The user must verify their email again to start fresh.
+      // This prevents potential duplicate resource creation on retry.
+
+      return {
+        success: false,
+        message: "Account creation failed. Please verify your email again to retry.",
+      };
+    }
+  }
+
   // ============================================================================
   // Private Helpers
   // ============================================================================
@@ -593,6 +842,41 @@ export class GetStartedWorkflowService {
     }
   }
 
+  private async sendWelcomeWithEligibilityEmail(
+    email: string,
+    firstName: string,
+    eligibilityRequestId: string
+  ): Promise<void> {
+    const appBase = this.config.get<string>("APP_BASE_URL", "http://localhost:3000");
+    const templateId = this.config.get<string>("EMAIL_TEMPLATE_WELCOME_WITH_ELIGIBILITY");
+
+    if (templateId) {
+      await this.emailService.sendEmail({
+        to: email,
+        subject: "Welcome! Your account is ready",
+        templateId,
+        dynamicTemplateData: {
+          firstName,
+          portalUrl: appBase,
+          dashboardUrl: `${appBase}/account/dashboard`,
+          eligibilityRequestId,
+        },
+      });
+    } else {
+      await this.emailService.sendEmail({
+        to: email,
+        subject: "Welcome! Your account is ready",
+        html: `
+          <p>Hi ${firstName},</p>
+          <p>Welcome! Your account has been created successfully.</p>
+          <p>We're also checking internet availability at your address. We'll notify you of the results within 1-2 business days.</p>
+          <p>Reference ID: ${eligibilityRequestId}</p>
+          <p>Log in to your dashboard: <a href="${appBase}/account/dashboard">${appBase}/account/dashboard</a></p>
+        `,
+      });
+    }
+  }
+
   private async determineAccountStatus(
     email: string
   ): Promise<{ status: AccountStatus; sfAccountId?: string; whmcsClientId?: number }> {

apps/bff/src/modules/auth/infra/workflows/signup-workflow.service.ts

@@ -134,20 +134,20 @@ export class SignupWorkflowService {
         lastName,
         email,
         password,
-        company: company ?? undefined,
+        ...(company ? { company } : {}),
         phone: phone,
         address: {
           address1: address!.address1!,
-          address2: address?.address2 ?? undefined,
+          ...(address?.address2 ? { address2: address.address2 } : {}),
           city: address!.city!,
           state: address!.state!,
           postcode: address!.postcode!,
           country: address!.country!,
         },
         customerNumber: customerNumberForWhmcs,
-        dateOfBirth,
+        ...(dateOfBirth ? { dateOfBirth } : {}),
-        gender,
+        ...(gender ? { gender } : {}),
-        nationality,
+        ...(nationality ? { nationality } : {}),
       });
 
       // Step 5: Create user and mapping in database
@@ -228,7 +228,7 @@ export class SignupWorkflowService {
         status: PORTAL_STATUS_ACTIVE,
         source,
         lastSignedInAt: new Date(),
-        whmcsAccountId,
+        ...(whmcsAccountId === undefined ? {} : { whmcsAccountId }),
       });
     } catch (error) {
       this.logger.warn("Failed to update Salesforce portal flags after signup", {

apps/bff/src/modules/auth/infra/workflows/signup/signup.types.ts

@@ -7,8 +7,8 @@
  */
 export interface SignupAccountSnapshot {
   id: string;
-  Name?: string | null;
+  Name?: string | null | undefined;
-  WH_Account__c?: string | null;
+  WH_Account__c?: string | null | undefined;
 }
 
 /**
@@ -38,14 +38,14 @@ export interface SignupPreflightResult {
   };
   portal: {
     userExists: boolean;
-    needsPasswordSet?: boolean;
+    needsPasswordSet?: boolean | undefined;
   };
   salesforce: {
-    accountId?: string;
+    accountId?: string | undefined;
     alreadyMapped: boolean;
   };
   whmcs: {
     clientExists: boolean;
-    clientId?: number;
+    clientId?: number | undefined;
   };
 }

apps/bff/src/modules/auth/presentation/http/auth.controller.ts

@@ -215,12 +215,12 @@ export class AuthController {
     @Req() req: RequestWithCookies,
     @Res({ passthrough: true }) res: Response
   ) {
-    const refreshToken = body.refreshToken ?? req.cookies?.refresh_token;
+    const refreshToken = body.refreshToken ?? req.cookies?.["refresh_token"];
     const rawUserAgent = req.headers["user-agent"];
     const userAgent = typeof rawUserAgent === "string" ? rawUserAgent : undefined;
     const result = await this.authFacade.refreshTokens(refreshToken, {
-      deviceId: body.deviceId,
+      deviceId: body.deviceId ?? undefined,
-      userAgent,
+      userAgent: userAgent ?? undefined,
     });
     this.setAuthCookies(res, result.tokens);
     return { user: result.user, session: this.toSession(result.tokens) };

apps/bff/src/modules/auth/presentation/http/get-started.controller.ts

@@ -18,6 +18,8 @@ import {
   completeAccountRequestSchema,
   maybeLaterRequestSchema,
   maybeLaterResponseSchema,
+  signupWithEligibilityRequestSchema,
+  signupWithEligibilityResponseSchema,
 } from "@customer-portal/domain/get-started";
 
 import { GetStartedWorkflowService } from "../../infra/workflows/get-started-workflow.service.js";
@@ -34,6 +36,8 @@ class GuestEligibilityResponseDto extends createZodDto(guestEligibilityResponseS
 class CompleteAccountRequestDto extends createZodDto(completeAccountRequestSchema) {}
 class MaybeLaterRequestDto extends createZodDto(maybeLaterRequestSchema) {}
 class MaybeLaterResponseDto extends createZodDto(maybeLaterResponseSchema) {}
+class SignupWithEligibilityRequestDto extends createZodDto(signupWithEligibilityRequestSchema) {}
+class SignupWithEligibilityResponseDto extends createZodDto(signupWithEligibilityResponseSchema) {}
 
 const ACCESS_COOKIE_PATH = "/api";
 const REFRESH_COOKIE_PATH = "/api/auth/refresh";
@@ -177,7 +181,7 @@ export class GetStartedController {
 
     res.cookie("access_token", result.tokens.accessToken, {
       httpOnly: true,
-      secure: process.env.NODE_ENV === "production",
+      secure: process.env["NODE_ENV"] === "production",
       sameSite: "lax",
       path: ACCESS_COOKIE_PATH,
       maxAge: calculateCookieMaxAge(accessExpires),
@@ -185,7 +189,7 @@ export class GetStartedController {
 
     res.cookie("refresh_token", result.tokens.refreshToken, {
       httpOnly: true,
-      secure: process.env.NODE_ENV === "production",
+      secure: process.env["NODE_ENV"] === "production",
       sameSite: "lax",
       path: REFRESH_COOKIE_PATH,
       maxAge: calculateCookieMaxAge(refreshExpires),
@@ -200,4 +204,65 @@ export class GetStartedController {
       },
     };
   }
+
+  /**
+   * Full signup with eligibility check (inline flow)
+   * Creates SF Account + Case + WHMCS + Portal in one operation
+   *
+   * Used when user clicks "Create Account" on the eligibility check page.
+   * This is the primary signup path - creates all accounts at once after OTP verification.
+   *
+   * Returns auth tokens (sets httpOnly cookies)
+   *
+   * Rate limit: 5 per 15 minutes per IP
+   */
+  @Public()
+  @Post("signup-with-eligibility")
+  @HttpCode(200)
+  @UseGuards(RateLimitGuard, SalesforceWriteThrottleGuard)
+  @RateLimit({ limit: 5, ttl: 900 })
+  async signupWithEligibility(
+    @Body() body: SignupWithEligibilityRequestDto,
+    @Res({ passthrough: true }) res: Response
+  ): Promise<SignupWithEligibilityResponseDto | { user: unknown; session: unknown }> {
+    const result = await this.workflow.signupWithEligibility(body);
+
+    if (!result.success || !result.authResult) {
+      return {
+        success: false,
+        message: result.message,
+      };
+    }
+
+    // Set auth cookies (same pattern as complete-account)
+    const accessExpires = result.authResult.tokens.expiresAt;
+    const refreshExpires = result.authResult.tokens.refreshExpiresAt;
+
+    res.cookie("access_token", result.authResult.tokens.accessToken, {
+      httpOnly: true,
+      secure: process.env["NODE_ENV"] === "production",
+      sameSite: "lax",
+      path: ACCESS_COOKIE_PATH,
+      maxAge: calculateCookieMaxAge(accessExpires),
+    });
+
+    res.cookie("refresh_token", result.authResult.tokens.refreshToken, {
+      httpOnly: true,
+      secure: process.env["NODE_ENV"] === "production",
+      sameSite: "lax",
+      path: REFRESH_COOKIE_PATH,
+      maxAge: calculateCookieMaxAge(refreshExpires),
+    });
+
+    return {
+      success: true,
+      eligibilityRequestId: result.eligibilityRequestId,
+      user: result.authResult.user,
+      session: {
+        expiresAt: accessExpires,
+        refreshExpiresAt: refreshExpires,
+        tokenType: TOKEN_TYPE,
+      },
+    };
+  }
 }

apps/bff/src/modules/auth/presentation/http/guards/local-auth.guard.ts

@@ -11,8 +11,8 @@ export class LocalAuthGuard implements CanActivate {
     const request = context.switchToHttp().getRequest<Request>();
     const body = (request.body ?? {}) as Record<string, unknown>;
 
-    const email = typeof body.email === "string" ? body.email : "";
+    const email = typeof body["email"] === "string" ? body["email"] : "";
-    const password = typeof body.password === "string" ? body.password : "";
+    const password = typeof body["password"] === "string" ? body["password"] : "";
 
     if (!email || !password) {
       throw new UnauthorizedException("Invalid credentials");

apps/bff/src/modules/auth/utils/jwt-expiry.util.ts

@@ -23,7 +23,7 @@ export const parseJwtExpiry = (expiresIn: string | number | undefined | null): n
 
   const unit = trimmed.slice(-1);
   const valuePortion = trimmed.slice(0, -1);
-  const parsedValue = parseInt(valuePortion, 10);
+  const parsedValue = Number.parseInt(valuePortion, 10);
 
   const toSeconds = (multiplier: number) => {
     if (Number.isNaN(parsedValue) || parsedValue <= 0) {

apps/bff/src/modules/auth/utils/token-from-request.util.ts

@@ -24,7 +24,7 @@ const pickFirstStringHeader = (value: unknown): string | undefined => {
 };
 
 export const resolveAuthorizationHeader = (headers: RequestHeadersLike): string | undefined => {
-  const raw = headers?.authorization;
+  const raw = headers?.["authorization"];
   return pickFirstStringHeader(raw);
 };
 
@@ -41,6 +41,6 @@ export const extractAccessTokenFromRequest = (request: RequestWithCookies): stri
   const headerToken = extractBearerToken(request.headers);
   if (headerToken) return headerToken;
 
-  const cookieToken = request.cookies?.access_token;
+  const cookieToken = request.cookies?.["access_token"];
   return typeof cookieToken === "string" && cookieToken.length > 0 ? cookieToken : undefined;
 };

apps/bff/src/modules/billing/services/invoice-retrieval.service.ts

@@ -45,7 +45,7 @@ export class InvoiceRetrievalService {
         const invoiceList = await this.whmcsInvoiceService.getInvoices(whmcsClientId, userId, {
           page,
           limit,
-          status,
+          ...(status !== undefined && { status }),
         });
 
         this.logger.log(`Retrieved ${invoiceList.invoices.length} invoices for user ${userId}`, {
@@ -100,7 +100,7 @@ export class InvoiceRetrievalService {
     const queryStatus = status as "Paid" | "Unpaid" | "Cancelled" | "Overdue" | "Collections";
 
     return withErrorHandling(
-      () => this.getInvoices(userId, { page, limit, status: queryStatus }),
+      async () => this.getInvoices(userId, { page, limit, status: queryStatus }),
       this.logger,
       {
         context: `Get ${status} invoices for user ${userId}`,

apps/bff/src/modules/health/health.controller.ts

@@ -20,10 +20,10 @@ export class HealthController {
     // Database check
     try {
       await this.prisma.$queryRaw`SELECT 1`;
-      checks.database = "ok";
+      checks["database"] = "ok";
     } catch (error) {
       this.logger.error({ error }, "Database health check failed");
-      checks.database = "fail";
+      checks["database"] = "fail";
     }
 
     // Cache check
@@ -31,11 +31,11 @@ export class HealthController {
       const key = "health:check";
       await this.cache.set(key, { ok: true }, 5);
       const value = await this.cache.get<{ ok: boolean }>(key);
-      checks.cache = value?.ok ? "ok" : "fail";
+      checks["cache"] = value?.ok ? "ok" : "fail";
       await this.cache.del(key);
     } catch (error) {
       this.logger.error({ error }, "Cache health check failed");
-      checks.cache = "fail";
+      checks["cache"] = "fail";
     }
 
     const status = Object.values(checks).every(v => v === "ok") ? "ok" : "degraded";

apps/bff/src/modules/id-mappings/cache/mapping-cache.service.ts

@@ -57,7 +57,7 @@ export class MappingCacheService {
     if (mapping.sfAccountId) {
       keys.push(this.buildCacheKey("sfAccountId", mapping.sfAccountId));
     }
-    await Promise.all(keys.map(key => this.cacheService.del(key)));
+    await Promise.all(keys.map(async key => this.cacheService.del(key)));
     this.logger.debug(`Deleted mapping cache for user ${mapping.userId}`);
   }
 

apps/bff/src/modules/id-mappings/domain/contract.ts

@@ -10,7 +10,7 @@ export interface UserIdMapping {
   id: string;
   userId: string;
   whmcsClientId: number;
-  sfAccountId?: string | null;
+  sfAccountId?: string | null | undefined;
   createdAt: IsoDateTimeString | Date;
   updatedAt: IsoDateTimeString | Date;
 }
@@ -18,12 +18,12 @@ export interface UserIdMapping {
 export interface CreateMappingRequest {
   userId: string;
   whmcsClientId: number;
-  sfAccountId?: string;
+  sfAccountId?: string | undefined;
 }
 
 export interface UpdateMappingRequest {
-  whmcsClientId?: number;
+  whmcsClientId?: number | undefined;
-  sfAccountId?: string;
+  sfAccountId?: string | undefined;
 }
 
 /**

apps/bff/src/modules/id-mappings/domain/validation.ts

@@ -98,10 +98,11 @@ export function validateDeletion(
  * The schema handles validation; this is purely for data cleanup.
  */
 export function sanitizeCreateRequest(request: CreateMappingRequest): CreateMappingRequest {
+  const trimmedSfAccountId = request.sfAccountId?.trim();
   return {
     userId: request.userId?.trim(),
     whmcsClientId: request.whmcsClientId,
-    sfAccountId: request.sfAccountId?.trim() || undefined,
+    ...(trimmedSfAccountId ? { sfAccountId: trimmedSfAccountId } : {}),
   };
 }
 
@@ -112,14 +113,15 @@ export function sanitizeCreateRequest(request: CreateMappingRequest): CreateMapp
  * The schema handles validation; this is purely for data cleanup.
  */
 export function sanitizeUpdateRequest(request: UpdateMappingRequest): UpdateMappingRequest {
-  const sanitized: Partial<UpdateMappingRequest> = {};
+  const sanitized: UpdateMappingRequest = {};
 
   if (request.whmcsClientId !== undefined) {
     sanitized.whmcsClientId = request.whmcsClientId;
   }
 
-  if (request.sfAccountId !== undefined) {
+  const trimmedSfAccountId = request.sfAccountId?.trim();
-    sanitized.sfAccountId = request.sfAccountId?.trim() || undefined;
+  if (trimmedSfAccountId) {
+    sanitized.sfAccountId = trimmedSfAccountId;
   }
 
   return sanitized;

apps/bff/src/modules/id-mappings/mappings.service.ts

@@ -80,7 +80,13 @@ export class MappingsService {
 
       let created;
       try {
-        created = await this.prisma.idMapping.create({ data: sanitizedRequest });
+        // Convert undefined to null for Prisma compatibility
+        const prismaData = {
+          userId: sanitizedRequest.userId,
+          whmcsClientId: sanitizedRequest.whmcsClientId,
+          sfAccountId: sanitizedRequest.sfAccountId ?? null,
+        };
+        created = await this.prisma.idMapping.create({ data: prismaData });
       } catch (e) {
         const msg = extractErrorMessage(e);
         if (msg.includes("P2002") || /unique/i.test(msg)) {
@@ -245,9 +251,18 @@ export class MappingsService {
         }
       }
 
+      // Convert undefined to null for Prisma compatibility
+      const prismaUpdateData: Prisma.IdMappingUpdateInput = {
+        ...(sanitizedUpdates.whmcsClientId !== undefined && {
+          whmcsClientId: sanitizedUpdates.whmcsClientId,
+        }),
+        ...(sanitizedUpdates.sfAccountId !== undefined && {
+          sfAccountId: sanitizedUpdates.sfAccountId ?? null,
+        }),
+      };
       const updated = await this.prisma.idMapping.update({
         where: { userId },
-        data: sanitizedUpdates,
+        data: prismaUpdateData,
       });
 
       const newMapping = mapPrismaMappingToDomain(updated);

apps/bff/src/modules/me-status/me-status.service.ts

@@ -186,32 +186,32 @@ export class MeStatusService {
 
     // Priority 3: pending orders
     if (orders && orders.length > 0) {
-      const pendingOrders = orders.filter(
+      const pendingOrder = orders.find(
         o =>
           o.status === "Draft" ||
           o.status === "Pending" ||
           (o.status === "Activated" && o.activationStatus !== "Completed")
       );
 
-      if (pendingOrders.length > 0) {
+      const firstPendingOrder = pendingOrder;
-        const order = pendingOrders[0];
+      if (firstPendingOrder) {
         const statusText =
-          order.status === "Pending"
+          firstPendingOrder.status === "Pending"
             ? "awaiting review"
-            : order.status === "Draft"
+            : firstPendingOrder.status === "Draft"
               ? "in draft"
               : "being activated";
 
         tasks.push({
-          id: `order-${order.id}`,
+          id: `order-${firstPendingOrder.id}`,
           priority: 3,
           type: "order",
           title: "Order in progress",
-          description: `${order.orderType || "Your"} order is ${statusText}`,
+          description: `${firstPendingOrder.orderType || "Your"} order is ${statusText}`,
           actionLabel: "View details",
-          detailHref: `/account/orders/${order.id}`,
+          detailHref: `/account/orders/${firstPendingOrder.id}`,
           tone: "info",
-          metadata: { orderId: order.id },
+          metadata: { orderId: firstPendingOrder.id },
         });
       }
     }

apps/bff/src/modules/notifications/notifications.service.ts

@@ -36,12 +36,12 @@ const NOTIFICATION_DEDUPE_WINDOW_HOURS: Partial<Record<NotificationTypeValue, nu
 export interface CreateNotificationParams {
   userId: string;
   type: NotificationTypeValue;
-  title?: string;
+  title?: string | undefined;
-  message?: string;
+  message?: string | undefined;
-  actionUrl?: string;
+  actionUrl?: string | undefined;
-  actionLabel?: string;
+  actionLabel?: string | undefined;
-  source?: NotificationSourceValue;
+  source?: NotificationSourceValue | undefined;
-  sourceId?: string;
+  sourceId?: string | undefined;
 }
 
 @Injectable()

apps/bff/src/modules/orders/orders.controller.ts

@@ -109,13 +109,13 @@ export class OrdersController {
       req.user?.id
     );
 
-    const uniqueSkus = Array.from(
+    const uniqueSkus = [
-      new Set(
+      ...new Set(
         cart.items
           .map(item => item.sku)
           .filter((sku): sku is string => typeof sku === "string" && sku.trim().length > 0)
-      )
+      ),
-    );
+    ];
 
     if (uniqueSkus.length === 0) {
       throw new NotFoundException("Checkout session contains no items");

apps/bff/src/modules/orders/queue/provisioning.queue.ts

@@ -47,6 +47,6 @@ export class ProvisioningQueueService {
 
   async depth(): Promise<number> {
     const counts = await this.queue.getJobCounts("waiting", "active", "delayed");
-    return (counts.waiting || 0) + (counts.active || 0) + (counts.delayed || 0);
+    return (counts["waiting"] || 0) + (counts["active"] || 0) + (counts["delayed"] || 0);
   }
 }

apps/bff/src/modules/orders/services/checkout.service.ts

@@ -448,7 +448,11 @@ export class CheckoutService {
       return { fee: defaultFee, autoAdded: true };
     }
 
-    return { fee: activationFees[0], autoAdded: true };
+    const firstFee = activationFees[0];
+    if (!firstFee) {
+      return null;
+    }
+    return { fee: firstFee, autoAdded: true };
   }
 
   /**
@@ -460,14 +464,14 @@ export class CheckoutService {
     // Handle various addon selection formats
     if (selections.addonSku) refs.add(selections.addonSku);
     if (selections.addons) {
-      selections.addons
+      for (const value of selections.addons
         .split(",")
         .map(value => value.trim())
-        .filter(Boolean)
+        .filter(Boolean))
-        .forEach(value => refs.add(value));
+        refs.add(value);
     }
 
-    return Array.from(refs);
+    return [...refs];
   }
 
   /**

apps/bff/src/modules/orders/services/order-builder.service.ts

@@ -124,7 +124,7 @@ export class OrderBuilder {
     try {
       const profile = await this.usersFacade.getProfile(userId);
       const address = profile.address;
-      const orderAddress = (body.configurations as Record<string, unknown>)?.address as
+      const orderAddress = (body.configurations as Record<string, unknown>)?.["address"] as
         | Record<string, unknown>
         | undefined;
       const addressChanged = !!orderAddress;

apps/bff/src/modules/orders/services/order-fulfillment-error.service.ts

@@ -43,7 +43,7 @@ export class OrderFulfillmentErrorService {
    * Get user-friendly error message for external consumption
    * Ensures no sensitive information is exposed
    */
-  getUserFriendlyMessage(error: unknown, errorCode: OrderFulfillmentErrorCode): string {
+  getUserFriendlyMessage(_error: unknown, errorCode: OrderFulfillmentErrorCode): string {
     switch (errorCode) {
       case ORDER_FULFILLMENT_ERROR_CODE.PAYMENT_METHOD_MISSING:
         return "Payment method missing - please add a payment method before fulfillment";

apps/bff/src/modules/orders/services/order-fulfillment-orchestrator.service.ts

@@ -31,18 +31,18 @@ type WhmcsOrderItemMappingResult = ReturnType<typeof mapOrderToWhmcsItems>;
 export interface OrderFulfillmentStep {
   step: string;
   status: "pending" | "in_progress" | "completed" | "failed";
-  startedAt?: Date;
+  startedAt?: Date | undefined;
-  completedAt?: Date;
+  completedAt?: Date | undefined;
-  error?: string;
+  error?: string | undefined;
 }
 
 export interface OrderFulfillmentContext {
   sfOrderId: string;
   idempotencyKey: string;
   validation: OrderFulfillmentValidationResult | null;
-  orderDetails?: OrderDetails;
+  orderDetails?: OrderDetails | undefined;
-  mappingResult?: WhmcsOrderItemMappingResult;
+  mappingResult?: WhmcsOrderItemMappingResult | undefined;
-  whmcsResult?: WhmcsOrderResult;
+  whmcsResult?: WhmcsOrderResult | undefined;
   steps: OrderFulfillmentStep[];
 }
 
@@ -92,7 +92,7 @@ export class OrderFulfillmentOrchestrator {
       idempotencyKey,
       validation: null,
       steps: this.initializeSteps(
-        typeof payload.orderType === "string" ? payload.orderType : "Unknown"
+        typeof payload["orderType"] === "string" ? payload["orderType"] : "Unknown"
       ),
     };
 
@@ -105,6 +105,7 @@ export class OrderFulfillmentOrchestrator {
       // Step 1: Validation (no rollback needed)
       this.updateStepStatus(context, "validation", "in_progress");
       try {
+        // eslint-disable-next-line require-atomic-updates -- context is not shared across concurrent executions
         context.validation = await this.orderFulfillmentValidator.validateFulfillmentRequest(
           sfOrderId,
           idempotencyKey
@@ -146,6 +147,7 @@ export class OrderFulfillmentOrchestrator {
             idempotencyKey,
           });
         }
+        // eslint-disable-next-line require-atomic-updates -- context is not shared across concurrent executions
         context.orderDetails = orderDetails;
       } catch (error) {
         this.logger.error("Failed to get order details", {
@@ -197,7 +199,7 @@ export class OrderFulfillmentOrchestrator {
             {
               id: "order_details",
               description: "Retain order details in context",
-              execute: this.createTrackedStep(context, "order_details", () =>
+              execute: this.createTrackedStep(context, "order_details", async () =>
                 Promise.resolve(context.orderDetails)
               ),
               critical: false,
@@ -205,7 +207,7 @@ export class OrderFulfillmentOrchestrator {
             {
               id: "mapping",
               description: "Map OrderItems to WHMCS format",
-              execute: this.createTrackedStep(context, "mapping", () => {
+              execute: this.createTrackedStep(context, "mapping", async () => {
                 if (!context.orderDetails) {
                   return Promise.reject(new Error("Order details are required for mapping"));
                 }
@@ -263,7 +265,7 @@ export class OrderFulfillmentOrchestrator {
                 whmcsCreateResult = result;
                 return result;
               }),
-              rollback: () => {
+              rollback: async () => {
                 if (whmcsCreateResult?.orderId) {
                   // Note: WHMCS doesn't have an automated cancel API
                   // Manual intervention required for order cleanup
@@ -297,7 +299,7 @@ export class OrderFulfillmentOrchestrator {
                 await this.whmcsOrderService.acceptOrder(whmcsCreateResult.orderId, sfOrderId);
                 return { orderId: whmcsCreateResult.orderId };
               }),
-              rollback: () => {
+              rollback: async () => {
                 if (whmcsCreateResult?.orderId) {
                   // Note: WHMCS doesn't have an automated cancel API for accepted orders
                   // Manual intervention required for service termination
@@ -320,7 +322,7 @@ export class OrderFulfillmentOrchestrator {
               description: "SIM-specific fulfillment (if applicable)",
               execute: this.createTrackedStep(context, "sim_fulfillment", async () => {
                 if (context.orderDetails?.orderType === "SIM") {
-                  const configurations = this.extractConfigurations(payload.configurations);
+                  const configurations = this.extractConfigurations(payload["configurations"]);
                   await this.simFulfillmentService.fulfillSimOrder({
                     orderDetails: context.orderDetails,
                     configurations,
@@ -444,7 +446,9 @@ export class OrderFulfillmentOrchestrator {
       }
 
       // Update context with results
+      // eslint-disable-next-line require-atomic-updates -- context is not shared across concurrent executions
       context.mappingResult = mappingResult;
+      // eslint-disable-next-line require-atomic-updates -- context is not shared across concurrent executions
       context.whmcsResult = whmcsCreateResult;
 
       this.logger.log("Transactional fulfillment completed successfully", {
@@ -584,8 +588,8 @@ export class OrderFulfillmentOrchestrator {
           this.orderFulfillmentErrorService.getShortCode(error) || String(errorCode)
         )
           .toString()
-          .substring(0, 60),
+          .slice(0, 60),
-        Activation_Error_Message__c: userMessage?.substring(0, 255),
+        Activation_Error_Message__c: userMessage?.slice(0, 255),
       };
 
       await this.salesforceService.updateOrder(updates as { Id: string; [key: string]: unknown });
@@ -608,8 +612,8 @@ export class OrderFulfillmentOrchestrator {
   getFulfillmentSummary(context: OrderFulfillmentContext): {
     success: boolean;
     status: "Already Fulfilled" | "Fulfilled" | "Failed";
-    whmcsOrderId?: string;
+    whmcsOrderId?: string | undefined;
-    whmcsServiceIds?: number[];
+    whmcsServiceIds?: number[] | undefined;
     message: string;
     steps: OrderFulfillmentStep[];
   } {
@@ -617,21 +621,24 @@ export class OrderFulfillmentOrchestrator {
     const failedStep = context.steps.find((s: OrderFulfillmentStep) => s.status === "failed");
 
     if (context.validation?.isAlreadyProvisioned) {
+      const whmcsOrderId = context.validation.whmcsOrderId;
       return {
         success: true,
         status: "Already Fulfilled",
-        whmcsOrderId: context.validation.whmcsOrderId,
+        ...(whmcsOrderId !== undefined && { whmcsOrderId }),
         message: "Order was already fulfilled in WHMCS",
         steps: context.steps,
       };
     }
 
     if (isSuccess) {
+      const whmcsOrderId = context.whmcsResult?.orderId.toString();
+      const whmcsServiceIds = context.whmcsResult?.serviceIds;
       return {
         success: true,
         status: "Fulfilled",
-        whmcsOrderId: context.whmcsResult?.orderId.toString(),
+        ...(whmcsOrderId !== undefined && { whmcsOrderId }),
-        whmcsServiceIds: context.whmcsResult?.serviceIds,
+        ...(whmcsServiceIds !== undefined && { whmcsServiceIds }),
         message: "Order fulfilled successfully in WHMCS",
         steps: context.steps,
       };
@@ -640,7 +647,7 @@ export class OrderFulfillmentOrchestrator {
     return {
       success: false,
       status: "Failed",
-      message: failedStep?.error || "Fulfillment failed",
+      message: failedStep?.error ?? "Fulfillment failed",
       steps: context.steps,
     };
   }
@@ -658,13 +665,17 @@ export class OrderFulfillmentOrchestrator {
     if (status === "in_progress") {
       step.status = "in_progress";
       step.startedAt = timestamp;
-      step.error = undefined;
+      delete step.error;
       return;
     }
 
     step.status = status;
     step.completedAt = timestamp;
-    step.error = status === "failed" ? error : undefined;
+    if (status === "failed" && error !== undefined) {
+      step.error = error;
+    } else {
+      delete step.error;
+    }
   }
 
   private createTrackedStep<TResult>(

apps/bff/src/modules/orders/services/order-fulfillment-validator.service.ts

@@ -4,9 +4,11 @@ import { SalesforceService } from "@bff/integrations/salesforce/salesforce.servi
 import { MappingsService } from "@bff/modules/id-mappings/mappings.service.js";
 import { extractErrorMessage } from "@bff/core/utils/error.util.js";
 import { sfOrderIdParamSchema } from "@customer-portal/domain/orders";
-import type { OrderFulfillmentValidationResult } from "@customer-portal/domain/orders/providers";
+import type {
+  OrderFulfillmentValidationResult,
+  SalesforceOrderRecord,
+} from "@customer-portal/domain/orders/providers";
 import { salesforceAccountIdSchema } from "@customer-portal/domain/common";
-import type { SalesforceOrderRecord } from "@customer-portal/domain/orders/providers";
 import { PaymentValidatorService } from "./payment-validator.service.js";
 
 /**