Fastify — Fast & Low Overhead Web Framework for Node.js

What Fastify Does

• HTTP server — built on Node http with optimized routing (find-my-way)
• Schema validation — JSON Schema for body/params/query/headers
• Serialization — fast JSON output via fast-json-stringify
• Plugin system — encapsulated context with fastify-plugin
• Hooks — onRequest, preHandler, onSend, onResponse lifecycle
• Logging — Pino by default (fastest JSON logger)

Architecture

Plugin tree: each plugin creates an encapsulated context. Decorators attach state to request/reply/instance. Schema compilation happens once at startup for zero-cost runtime validation.

Self-Hosting

# Production
NODE_ENV=production node server.js

# Docker
FROM node:20-alpine
WORKDIR /app
COPY package*.json ./
RUN npm ci --only=production
COPY . .
CMD ["node", "server.js"]

Key Features

• ~2x faster than Express in benchmarks
• Native TypeScript types
• JSON Schema validation + serialization
• Request lifecycle hooks
• Plugin encapsulation
• HTTP/2 support
• Async/await first-class
• Graceful shutdown built-in

Comparison

FAQ

Q: Can it replace Express? A: Yes. The @fastify/express compatibility layer supports most Express middleware.

Q: Why is it so fast? A: Optimized routing (radix tree) + compile-time schema serialization (fast-json-stringify) + Pino logging.

Q: Can NestJS use Fastify? A: Yes. NestJS officially supports a Fastify adapter that replaces the default Express.

Sources & Credits

• Docs: https://www.fastify.dev
• GitHub: https://github.com/fastify/fastify
• License: MIT