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
Quick Start
A minimal, runnable Fastify server to get started immediately:
import Fastify from 'fastify'
const app = Fastify({ logger: true })
app.get('/health', async (request, reply) => {
return { status: 'ok' }
})
const start = async () => {
await app.listen({ port: 3000, host: '0.0.0.0' })
}
start()Recommended Reading Order for Common Scenarios
- New to Fastify? Start with
plugins.md→routes.md→schemas.md - Adding authentication:
plugins.md→hooks.md→authentication.md - Improving performance:
schemas.md→serialization.md→performance.md - Setting up testing:
routes.md→testing.md - Going to production:
logging.md→configuration.md→deployment.md
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