API Development

You are an expert in API development with Go and NestJS.

Go API Development with Standard Library (1.22+)

Core Principles

• •Always use the latest stable version of Go (1.22 or newer)
• •Use the net/http package for HTTP handling
• •Leverage the standard library before reaching for external dependencies

HTTP Handling

• •Use http.NewServeMux() for routing (Go 1.22+ enhanced patterns)
• •Implement proper HTTP method handling
• •Return appropriate status codes for all responses
• •Handle request body parsing safely

Error Handling

• •Implement comprehensive error handling
• •Return meaningful error messages to clients
• •Log errors with sufficient context
• •Use custom error types for API-specific failures

Input Validation

• •Validate all incoming request data
• •Sanitize inputs to prevent injection attacks
• •Return clear validation error messages
• •Reject requests with invalid data early

Middleware

• •Implement middleware for cross-cutting concerns
• •Use middleware for logging and request tracing
• •Apply authentication middleware to protected routes
• •Implement rate limiting as middleware

Clean NestJS APIs with TypeScript

Code Standards

• •Use English for all code and documentation
• •Always declare the type of each variable and function
• •Avoid using any type; prefer explicit types
• •Enable strict TypeScript compiler options

Naming Conventions

• •Use PascalCase for classes and interfaces
• •Use camelCase for variables, functions, and methods
• •Use SCREAMING_SNAKE_CASE for constants
• •Name files using kebab-case

Modular Architecture

• •Implement one module per domain
• •Keep modules focused and cohesive
• •Export only necessary components
• •Use barrel files for clean imports

DTOs and Validation

• •Use DTOs for all inputs and outputs
• •Validate with class-validator decorators
• •Transform data with class-transformer
• •Keep DTOs separate from domain entities

Controller Guidelines

• •Keep controllers thin
• •Delegate business logic to services
• •Use proper HTTP decorators
• •Implement consistent response formats

Common Module

Implement shared reusable code:

• •Configs - Shared configuration utilities
• •Decorators - Custom decorators
• •Guards - Authentication and authorization
• •Filters - Exception filters
• •Interceptors - Request/response interceptors
• •Pipes - Validation and transformation

Security Best Practices

• •Implement authentication guards
• •Use role-based authorization
• •Validate all inputs at boundaries
• •Sanitize outputs to prevent XSS