fastify-uws

A performant HTTP and WebSocket server for Fastify with uWebSockets.

Installation

Install @jmealo/fastify-uws with your favorite package manager:

$ npm i @jmealo/fastify-uws
# or
$ yarn add @jmealo/fastify-uws
# or
$ pnpm i @jmealo/fastify-uws
# or
$ bun add @jmealo/fastify-uws

Supported

fastify-uws v1.x supports the following versions:

• Node.js: v20, v22, and v24
• fastify: v5.x
• @fastify/websocket: v11.x

Release (CD)

GitHub Actions publishes to npm on semver tags (v*.*.*) via cd.yml using npm Trusted Publishing (OIDC).

One-time npm setup (no NPM_TOKEN secret needed):

• npm package: @jmealo/fastify-uws
• npm trusted publisher:
  • Owner: jmealo
  • Repository: jmealo/fastify-uws
  • Workflow file: .github/workflows/cd.yml
  • Environment: leave empty unless you deliberately scope to a GitHub Environment

Usage

Just two lines are needed to speed up your Fastify application.

// app.ts
import fastify from 'fastify';
import { serverFactory } from '@jmealo/fastify-uws'; // Import here

import router from '~/plugins/router';

export default () => {
  const app = fastify({
    logger: {
      transport: {
        target: '@fastify/one-line-logger',
      },
    },
    serverFactory, // And use here
  });

  app.register(router);

  return app;
};

// server.ts
import app from './app';

const server = app();

const start = async () => {
  try {
    await server.listen({
      host: '127.0.0.1',
      port: 3000,
    });
  } catch (err) {
    server.log.error(err);
    process.exit(1);
  }
};

start();

Use Fetch

// src/routes/hello-http/+handler.ts
import type { FastifyPluginAsyncTypebox } from '@fastify/type-provider-typebox';
import { Type } from 'typebox';

export default (async (app) => {
  app.get(
    '',
    {
      schema: {
        response: {
          200: Type.Object({
            message: Type.String(),
          }),
        },
      },
    },
    async (req, reply) => {
      return reply.send({
        message: 'Hello, World!',
      });
    },
  );
}) as FastifyPluginAsyncTypebox;

With FormData

// app.ts
import multipart from '@fastify/multipart';

app.register(multipart);

// src/routes/hello-fd/+handler.ts
import type { FastifyPluginAsyncTypebox } from '@fastify/type-provider-typebox';
import fs from 'node:fs';
import { pipeline } from 'node:stream/promises';

export default (async (app) => {
  app.post('', async (req, reply) => {
    const data = await req.file();

    data.file; // stream
    data.fields; // other parsed parts
    data.fieldname;
    data.filename;
    data.encoding;
    data.mimetype;

    await pipeline(data.file, fs.createWriteStream(data.filename));
    // or
    // await data.toBuffer(); // Buffer

    return reply.send({ message: 'ok' });
  });
}) as FastifyPluginAsyncTypebox;

Use WebSocket

Just a single line of change can speed up your WebSocket application in Fastify.

- import websocket from '@fastify/websocket';
+ import { websocket } from '@jmealo/fastify-uws';

// app.ts
import { websocket } from '@jmealo/fastify-uws';

app.register(websocket);

// src/routes/hello-ws/+handler.ts
import type { FastifyPluginAsyncTypebox } from '@fastify/type-provider-typebox';

export default (async (app) => {
  // $ node client-ws.mjs
  app.get('', { websocket: true }, (socket) => {
    app.log.info('Client connected');

    socket.on('message', (message: MessageEvent) => {
      console.log(`Client message: ${message}`);
      socket.send('Hello from Fastify!');
    });

    socket.on('close', () => {
      app.log.info('Client disconnected');
    });
  });
}) as FastifyPluginAsyncTypebox;

Use EventSource

// app.ts
import sse from '@fastify/sse';

app.register(sse);

// src/routes/hello-sse/+handler.ts
import type { FastifyPluginAsyncTypebox } from '@fastify/type-provider-typebox';

export default (async (app) => {
  // $ node client-es.mjs
  app.get('', { sse: true }, async (request, reply) => {
    app.log.info('Client connected');

    await reply.sse.send({ data: 'Hello from Fastify!' });

    request.raw.on('close', () => {
      app.log.info('Client disconnected');
    });
  });
}) as FastifyPluginAsyncTypebox;

TLS/SSL: http2 and https

import fs from 'node:fs';
import fastify from 'fastify';
import { serverFactory, websocket } from '@jmealo/fastify-uws';
// [...]
export default () => {
  const app = fastify({
    http2: true,
    https: {
      key: fs.readFileSync(process.env.HTTPS_KEY),
      cert: fs.readFileSync(process.env.HTTPS_CERT),
    },
    logger: {
      transport: {
        target: '@fastify/one-line-logger',
      },
    },
    serverFactory,
  });

  app.register(websocket);
  // [...]
};
// [...]

Benchmarks

Quick Comparison

Measured with pnpm bench — autocannon, 100 connections, 10s duration, pipelining 10

HTTP — GET /ping → { ok: true }

| | Req/sec | Latency (mean) | Latency (p99) | | :--- | ---: | ---: | ---: | | fastify | 93,000 | 10.3 ms | 26 ms | | fastify-uws | 200,000 | 4.6 ms | 9 ms | | | +115% | -55% | -65% |

WebSocket — 100 clients, 64B echo flood, 10s

| | Messages/sec | | :--- | ---: | | @fastify/websocket (ws) | 91,000 | | fastify-uws | 94,000 | | | +3% |

SSE — 100 clients, 64B events, 10s

| | Events/sec | | :--- | ---: | | @fastify/sse (default) | 420,000 | | @fastify/sse + fastify-uws | 197,000 | | | -53% |

Results vary by machine. Run pnpm bench to reproduce.

oha v1.4.5

$ oha -c 500 -z 10s --no-tui http://0.0.0.0:3000/api/hello-world

| | Version | Language | Router | Requests/sec | | :------------ | ------------: | :-------------- | -----: | -----------: | | hyper | 1.4.1 | Rust | ✗ | 56,175.6102 | | warp | 0.3.7 | Rust | ✓ | 55,868.5861 | | axum | 0.7.7 | Rust | ✓ | 54,588.2828 | | bun | 1.1.30 | TypeScript/Bun | ✗ | 54,098.4841 | | graphul | 1.0.1 | Rust | ✓ | 53,949.4400 | | poem | 3.1.0 | Rust | ✓ | 53,849.0781 | | uws | 20.48.0 | JavaScript/Node | ✗ | 52,802.8029 | | elysia | 1.1.17 | TypeScript/Bun | ✓ | 52,257.3305 | | | | | | ~ 5.5k ~ | | hyper-express | 6.17.2 | JavaScript/Node | ✓ | 46,745.4887 | | hono | 4.6.3 | TypeScript/Bun | ✓ | 46,685.6014 | | nhttp | 2.0.2 | TypeScript/Deno | ✓ | 44,874.2535 | | deno | 2.0.0 | TypeScript/Deno | ✗ | 44,753.8552 | | hono | 4.6.3 | TypeScript/Deno | ✓ | 43,280.7544 | | | | | | ~ 9.2k ~ | | h3 | 1.12.0 | TypeScript/Bun | ✓ | 34,043.4693 | | fastify-uws | 1.0.0 | JavaScript/Node | ✓ | 31,295.8715 | | polka | 1.0.0-next.28 | JavaScript/Node | ✓ | 31,086.5543 | | oak | 17.0.0 | TypeScript/Deno | ✓ | 30,730.7971 | | node | 20.18.0 | JavaScript/Node | ✗ | 29,230.1719 | | oak | 17.0.0 | TypeScript/Bun | ✓ | 27,449.3417 | | fastify | 5.0.0 | JavaScript/Node | ✓ | 27,408.6679 | | hono | 4.6.3 | JavaScript/Node | ✓ | 25,138.5659 | | | | | | ~ 4.9k ~ | | h3 | 1.12.0 | JavaScript/Node | ✓ | 20,193.2311 | | | | | | ~ 9.2k ~ | | express | 4.21.0 | JavaScript/Node | ✓ | 10,949.1532 |

Credits

This project is based on @geut/fastify-uws and is licensed under the MIT License.