Skills fastify-best-practices

Guides development of Fastify Node.js backend servers and REST APIs using TypeScript or JavaScript. Use when building, configuring, or debugging a Fastify application — including defining routes, implementing plugins, setting up JSON Schema validation, handling errors, optimising performance, managing authentication, configuring CORS and security headers, integrating databases, working with WebSockets, and deploying to production. Covers the full Fastify request lifecycle (hooks, serialization, logging with Pino) and TypeScript integration via strip types. Trigger terms: Fastify, Node.js server, REST API, API routes, backend framework, fastify.config, server.ts, app.ts.

install

source · Clone the upstream repo

git clone https://github.com/mcollina/skills

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/mcollina/skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/fastify" ~/.claude/skills/mcollina-skills-fastify-best-practices && rm -rf "$T"

manifest: skills/fastify/SKILL.md

source content

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()

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

Skills fastify-best-practices

When to use

Quick Start

Recommended Reading Order for Common Scenarios

How to use

Core Principles