Banking Application Blueprint

The Banking Application is a comprehensive, production-ready blueprint that demonstrates how to build a complete financial services backend using Express.js and MongoDB. This blueprint includes account management, fund transfers, transaction tracking, and a double-entry ledger system.

What You'll Build

A fully functional banking API with:

• User Account Management - Create and manage bank accounts
• Deposit & Withdrawal - Handle cash operations with validation
• Fund Transfers - Secure internal and external transfers
• Transaction History - Complete audit trail of all operations
• Double-Entry Ledger - Professional accounting system implementation
• OTP Verification - Secure critical operations with one-time passwords
• OAuth Integration - Support for third-party authentication providers
• File Upload - Document upload functionality for KYC and more

Features

Core Banking Features

• ✅ Account Management - Create multiple account types (savings, checking, business)
• ✅ Balance Operations - Deposit, withdraw, and check balance with validations
• ✅ Fund Transfers - Internal transfers between accounts with real-time updates
• ✅ Transaction Tracking - Complete history with filtering and pagination
• ✅ Ledger System - Double-entry bookkeeping for financial accuracy
• ✅ Audit Trail - Comprehensive logging of all financial operations

Security & Authentication

• ✅ JWT Authentication - Secure access tokens with refresh mechanism
• ✅ OTP Verification - Two-factor authentication for sensitive operations
• ✅ OAuth 2.0 - Google and GitHub authentication support
• ✅ Role-Based Access - Different permissions for users and admins
• ✅ Rate Limiting - Protection against brute-force attacks
• ✅ Input Validation - Comprehensive validation using Zod schemas

Technical Features

• ✅ MVC Architecture - Clean separation of concerns
• ✅ Feature-Based Modules - Domain-driven organization option
• ✅ Swagger Documentation - Auto-generated API docs
• ✅ Error Handling - Centralized error handling with custom errors
• ✅ Logging - Winston-based structured logging
• ✅ TypeScript - Full type safety and IntelliSense support

Installation

Generate a new banking app project using the Servercn CLI:

pnpmnpmyarnbun

npx servercn-cli add blueprint banking-app

This will create a complete banking application with all the necessary modules, models, and routes.

Project Structure

MVC Architecture

The banking app follows the traditional Model-View-Controller pattern:

banking-app/
├── src/
│   ├── controllers/       # Request handlers
│   │   ├── auth.controller.ts
│   │   ├── account.controller.ts
│   │   ├── transaction.controller.ts
│   │   └── ledger.controller.ts
│   ├── models/           # MongoDB schemas
│   │   ├── User.ts
│   │   ├── Account.ts
│   │   ├── Transaction.ts
│   │   └── Ledger.ts
│   ├── services/         # Business logic layer
│   │   ├── auth.service.ts
│   │   ├── account.service.ts
│   │   └── transaction.service.ts
│   ├── routes/           # API route definitions
│   │   ├── auth.routes.ts
│   │   ├── account.routes.ts
│   │   └── transaction.routes.ts
│   ├── middlewares/      # Express middlewares
│   │   ├── auth.middleware.ts
│   │   ├── validation.middleware.ts
│   │   └── error.middleware.ts
│   ├── validators/       # Zod schemas
│   │   ├── auth.validator.ts
│   │   └── account.validator.ts
│   ├── utils/            # Utility functions
│   │   ├── apiResponse.ts
│   │   ├── catchAsync.ts
│   │   └── AppError.ts
│   ├── config/           # Configuration files
│   │   ├── database.ts
│   │   └── env.ts
│   └── app.ts            # Express app setup
├── package.json
└── tsconfig.json

Feature-Based Architecture

For better scalability and maintainability:

banking-app/
├── src/
│   ├── modules/          # Feature modules
│   │   ├── auth/
│   │   │   ├── auth.controller.ts
│   │   │   ├── auth.service.ts
│   │   │   ├── auth.routes.ts
│   │   │   ├── auth.model.ts
│   │   │   └── auth.validator.ts
│   │   ├── account/
│   │   │   ├── account.controller.ts
│   │   │   ├── account.service.ts
│   │   │   ├── account.routes.ts
│   │   │   ├── account.model.ts
│   │   │   └── account.dto.ts
│   │   ├── transaction/
│   │   ├── ledger/
│   │   ├── otp/
│   │   └── oauth/
│   ├── shared/           # Shared utilities
│   │   ├── middlewares/
│   │   ├── utils/
│   │   └── constants/
│   ├── config/
│   ├── types/
│   └── app.ts
├── package.json
└── tsconfig.json

Running the Application

## Development Mode
npm run dev
 
## Production Build
npm run build
 
## Start production server
npm start
 
##Type Checking
npm run typecheck
 
## Generate API Documentation
npm run docs
## This generates Swagger documentation at /api/docs.

API Documentation

Once running, access the interactive API documentation at: http://localhost:3000/api/docs

The Swagger UI provides:

• Interactive API testing
• Request/response examples
• Authentication helpers
• Schema definitions

API Endpoints

Health Check

Base URL: http://localhost:3000/api/v1/health

Authentication

Base URL: http://localhost:3000/api/v1/auth

Accounts

Base URL: http://localhost:3000/api/v1/accounts

Transactions

Base URL: http://localhost:3000/api/v1/transactions

OAuth

Base URL: http://localhost:3000/api/auth

Security Considerations

1. Password Hashing - bcrypt with salt rounds
2. JWT Tokens - Short-lived access tokens, long-lived refresh tokens
3. Rate Limiting - Per-IP and per-user limits
4. Input Validation - All inputs validated with Zod
5. SQL Injection Prevention - MongoDB prevents SQL injection
6. XSS Protection - Helmet middleware
7. CORS Configuration - Configurable allowed origins
8. Request Sanitization - Mongo-sanitize for NoSQL injection prevention

Best Practices Followed

• Never log sensitive data (passwords, tokens)
• Use HTTPS in production
• Rotate secrets regularly
• Implement account lockout after failed attempts
• Monitor for suspicious activity

Contributing

Found a bug or want to suggest improvements? Please contribute to the Servercn project!

Support

Need help? Join our Discord community or open an issue on GitHub.