fastify

v5.2.1MITTS Ready

Extremely fast and low overhead web framework, for Node.js, with built-in JSON schema validation.

96/ 100

Excellent Health

Weekly Downloads

4.8M

Bundle Size (gzip)

38 kB(135 kB min)

Dependencies

12 direct

Last Updated

2025-01-15

SPONSORED CLOUD & DEV TOOLS•Google Ads Partner

NPMBot AI Assessment

The modern production powerhouse for Node.js backends and high-load microservices.

Fastify is architected specifically to maximize Node.js performance through JIT compiled JSON serialization (fast-json-stringify) and highly optimized routing (find-my-way). With first-class TypeScript support and automatic schema validation, it is the best Node-native Express alternative.

Key Advantages

•Up to 3x faster than Express in JSON serialization and routing
•First-class TypeScript typing and built-in Ajv schema validation
•Plugin architecture with encapsulation ensures clean modular systems
•Built-in Pino logging with ultra-low CPU overhead

Gotchas & Limitations

•Plugin encapsulation model has a steeper learning curve for beginners
•Middlewares require @fastify/express adapter for Express compatibility

Recommended For:

Production Node.js microservices handling heavy request throughput, API backends demanding strict JSON schema validation

Avoid If:

Serverless functions where multi-runtime edge frameworks like Hono excel

FEATURED PARTNER•Google Ads Partner

Installation & Quickstart

Package Manager Command

javascript

npm install fastify

fastify Usage Example

javascript

import Fastify from 'fastify';

const server = Fastify({ logger: true });

server.get('/ping', async (request, reply) => {
  return { pong: 'it works!' };
});

await server.listen({ port: 3000 });

Compare fastify with Alternatives

Recommended Alternatives

hono-70% size

Works on Cloudflare Workers, Bun, and Node

express+40%

Simpler mental model but lower throughput

View full fastify alternatives radar →

Repository & Links

NPM Official Registry Official Documentation GitHub Repository