GoBank API

A production-grade banking/financial REST API built with Go, demonstrating enterprise-level development practices including clean architecture, robust security, high performance, and modern DevOps practices.

Features

Core Functionality

• User Management: Registration, authentication with JWT (access + refresh tokens), profile management
• Account Management: Create checking/savings accounts, multi-currency support (USD, EUR, GBP)
• Money Transfers: Transfer between accounts with full ACID compliance, idempotency support
• Transaction History: Complete audit trail with pagination

Technical Highlights

• Clean Architecture: Domain-driven design with clear separation of concerns
• Security: JWT authentication, bcrypt password hashing, rate limiting, audit logging
• Performance: Redis caching, PostgreSQL connection pooling, graceful shutdown
• DevOps: Docker, Kubernetes manifests, GitHub Actions CI/CD, Prometheus metrics

Tech Stack

Category	Technology
Language	Go 1.22+
Framework	Gin
Database	PostgreSQL 15+
Cache	Redis 7+
Authentication	JWT
Containerization	Docker
Orchestration	Kubernetes
CI/CD	GitHub Actions
Monitoring	Prometheus

Project Structure

gobank/
├── cmd/api/                    # Application entry point
├── internal/
│   ├── domain/                 # Business entities and interfaces
│   │   ├── entity/
│   │   ├── repository/
│   │   └── service/
│   ├── usecase/                # Business logic
│   ├── adapter/                # Interface adapters
│   │   ├── handler/            # HTTP handlers
│   │   ├── repository/         # Repository implementations
│   │   └── middleware/
│   ├── infrastructure/         # External services
│   │   ├── config/
│   │   ├── database/
│   │   ├── logger/
│   │   └── server/
│   └── pkg/                    # Shared utilities
├── migrations/                 # Database migrations
├── deployments/
│   ├── docker/
│   └── kubernetes/
└── .github/workflows/          # CI/CD pipelines

Getting Started

Prerequisites

• Go 1.22+
• Docker & Docker Compose
• PostgreSQL 15+ (or use Docker)
• Redis 7+ (or use Docker)
• Make (optional)

Quick Start with Docker

# Clone the repository
git clone https://github.com/yourusername/gobank.git
cd gobank

# Start all services
docker compose up -d

# The API will be available at http://localhost:8080

Local Development

# Install dependencies
go mod download

# Copy environment file
cp .env.example .env

# Run database migrations
make migrate-up

# Run the application
make run

API Endpoints

Authentication

Method	Endpoint	Description
POST	/api/v1/auth/register	Register new user
POST	/api/v1/auth/login	Login and get tokens
POST	/api/v1/auth/refresh	Refresh access token
POST	/api/v1/auth/logout	Invalidate refresh token

Users

Method	Endpoint	Description
GET	/api/v1/users/me	Get current user profile
PUT	/api/v1/users/me	Update profile

Accounts

Method	Endpoint	Description
POST	/api/v1/accounts	Create new account
GET	/api/v1/accounts	List user's accounts
GET	/api/v1/accounts/:id	Get account details
GET	/api/v1/accounts/:id/transactions	Get account transactions

Transfers

Method	Endpoint	Description
POST	/api/v1/transfers	Create transfer
GET	/api/v1/transfers	List transfers
GET	/api/v1/transfers/:id	Get transfer details

Health & Monitoring

Method	Endpoint	Description
GET	/health	Health check
GET	/ready	Readiness check
GET	/metrics	Prometheus metrics

API Usage Examples

Register a User

curl -X POST http://localhost:8080/api/v1/auth/register \
  -H "Content-Type: application/json" \
  -d '{
    "email": "[email protected]",
    "password": "securepassword123",
    "full_name": "John Doe"
  }'

Login

curl -X POST http://localhost:8080/api/v1/auth/login \
  -H "Content-Type: application/json" \
  -d '{
    "email": "[email protected]",
    "password": "securepassword123"
  }'

Create Account

curl -X POST http://localhost:8080/api/v1/accounts \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <access_token>" \
  -d '{
    "account_type": "checking",
    "currency": "USD"
  }'

Create Transfer

curl -X POST http://localhost:8080/api/v1/transfers \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer <access_token>" \
  -H "X-Idempotency-Key: unique-key-123" \
  -d '{
    "from_account_id": "uuid-from",
    "to_account_id": "uuid-to",
    "amount": "100.00"
  }'

Development

Available Make Commands

make build          # Build the application
make run            # Run the application
make test           # Run tests
make lint           # Run linter
make docker-up      # Start Docker services
make docker-down    # Stop Docker services
make migrate-up     # Run migrations
make migrate-down   # Rollback migrations
make help           # Show all commands

Running Tests

# Run all tests
make test

# Run tests with coverage
make test-coverage

Deployment

Docker

# Build Docker image
make docker-build

# Run with Docker Compose
docker compose up -d

Kubernetes

# Apply Kubernetes manifests
kubectl apply -f deployments/kubernetes/

Security Features

• JWT Authentication: Short-lived access tokens (15 min) with refresh token rotation
• Password Hashing: bcrypt with cost factor 12
• Rate Limiting: Redis-based sliding window rate limiting
• Input Validation: Comprehensive request validation
• SQL Injection Prevention: Parameterized queries throughout
• Audit Logging: All financial operations are logged
• Security Headers: CORS, Content-Type enforcement, XSS protection

Architecture Decisions

1. Clean Architecture: Separates business logic from infrastructure concerns
2. Repository Pattern: Abstracts data access for easy testing and switching databases
3. Dependency Injection: All dependencies are injected, enabling easy mocking
4. Database Transactions: Financial operations use proper transaction isolation
5. Idempotency: Transfer operations support idempotency keys

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.