fastify-best-practices

When to use

Use this skill when you need to:

• Develop backend applications using Fastify
• Implement Fastify plugins and route handlers
• Get guidance on Fastify architecture and patterns
• Use TypeScript with Fastify (strip types)
• Implement testing with Fastify’s inject method
• Configure validation, serialization, and error handling

How to use

Read individual rule files for detailed explanations and code examples:

• rules/plugins.md – Plugin development and encapsulation
• rules/routes.md – Route organization and handlers
• rules/schemas.md – JSON Schema validation
• rules/error-handling.md – Error handling patterns
• rules/hooks.md – Hooks and request lifecycle
• rules/authentication.md – Authentication and authorization
• rules/testing.md – Testing with inject()
• rules/performance.md – Performance optimization
• rules/logging.md – Logging with Pino
• rules/typescript.md – TypeScript integration
• rules/decorators.md – Decorators and extensions
• rules/content-type.md – Content type parsing
• rules/serialization.md – Response serialization
• rules/cors-security.md – CORS and security headers
• rules/websockets.md – WebSocket support
• rules/database.md – Database integration patterns
• rules/configuration.md – Application configuration
• rules/deployment.md – Production deployment
• rules/http-proxy.md – HTTP proxying and reply.from()

Core Principles

• Encapsulation: Fastify’s plugin system provides automatic encapsulation
• Schema-first: Define schemas for validation and serialization
• Performance: Fastify is optimized for speed; use its features correctly
• Async/await: All handlers and hooks support async functions
• Minimal dependencies: Prefer Fastify’s built-in features and official plugins