Building Scalable APIs with Node.js and TypeScript

Creating APIs that can scale with your application's growth requires careful planning and implementation of best practices.

Architecture Principles

Layered Architecture

**Controller Layer**: Handle HTTP requests/responses

**Service Layer**: Business logic implementation

**Repository Layer**: Data access abstraction

**Model Layer**: Data structure definitions

Design Patterns

**Dependency Injection** for loose coupling

**Repository Pattern** for data access

**Factory Pattern** for object creation

**Observer Pattern** for event handling

TypeScript Benefits

Type Safety

**Compile-time error** detection

**Better IDE support** with autocomplete

**Refactoring confidence** with type checking

**API contract** enforcement

Code Organization

**Interface definitions** for clear contracts

**Generic types** for reusable components

**Enum usage** for constants

**Namespace organization** for large projects

Performance Optimization

Database Optimization

**Connection pooling** for efficient resource usage

**Query optimization** with proper indexing

**Caching strategies** with Redis

**Database migrations** for schema management

API Performance

**Response compression** with gzip

**Rate limiting** to prevent abuse

**Pagination** for large datasets

**Async/await** for non-blocking operations

Error Handling

Structured Error Responses

```typescript

interface ApiError {

code: string;

message: string;

details?: any;

timestamp: string;

}

```

Error Categories

**Validation errors** (400)

**Authentication errors** (401)

**Authorization errors** (403)

**Not found errors** (404)

**Server errors** (500)

Testing Strategy

Test Types

**Unit tests** for individual functions

**Integration tests** for API endpoints

**End-to-end tests** for complete workflows

**Load tests** for performance validation

Testing Tools

**Jest** for unit testing

**Supertest** for API testing

**Artillery** for load testing

**Docker** for test environment isolation

Deployment Considerations

Environment Management

**Environment variables** for configuration

**Docker containers** for consistency

**Health checks** for monitoring

**Graceful shutdown** handling

Monitoring and Logging

**Structured logging** with Winston

**Application metrics** with Prometheus

**Error tracking** with Sentry

**Performance monitoring** with APM tools

Security Best Practices

Authentication & Authorization

**JWT tokens** for stateless auth

**Role-based access** control

**API key management** for external access

**OAuth integration** for third-party auth

Data Protection

**Input validation** and sanitization

**SQL injection** prevention

**XSS protection** measures

**HTTPS enforcement** in production

Conclusion

Building scalable APIs requires attention to:

**Clean architecture** patterns

**Type safety** with TypeScript

**Performance optimization** strategies

**Comprehensive testing** approaches

**Security best practices**

The investment in these practices pays off as your application grows and evolves.

Building Scalable APIs with Node.js and TypeScript

Building Scalable APIs with Node.js and TypeScript

Architecture Principles

Layered Architecture

Design Patterns

TypeScript Benefits

Type Safety

Code Organization

Performance Optimization

Database Optimization

API Performance

Error Handling

Structured Error Responses

Error Categories

Testing Strategy

Test Types

Testing Tools

Deployment Considerations

Environment Management

Monitoring and Logging

Security Best Practices

Authentication & Authorization

Data Protection

Conclusion

About Bahtiyar Karakoç

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