fastify – fastify

An efficient server implies a lower cost of the infrastructure, better
responsiveness under load, and happy users. How can you efficiently handle the
resources of your server, knowing that you are serving the highest number of
requests possible, without sacrificing security validations and handy
development?

Enter Fastify. Fastify is a web framework highly focused on providing the best
developer experience with the least overhead and a powerful plugin architecture.
It is inspired by Hapi and Express and as far as we know, it is one of the
fastest web frameworks in town.

The main branch refers to the Fastify v5 release.
Check out the <code class="ra0-md-code">4.x</code> branch for v4.

Table of Contents

• Quick start
• Install
• Example
• Core features
• Benchmarks
• Documentation
• Ecosystem
• Support
• Team
• Hosted by
• License

Quick start

Create a folder and make it your current working directory:

mkdir my-app
cd my-app

Generate a Fastify project with npm init:

npm init fastify

Install dependencies:

npm i

To start the app in dev mode:

npm run dev

For production mode:

npm start

Under the hood npm init downloads and runs [Fastify
Create](https://github.com/fastify/create-fastify), which in turn uses the
generate functionality of Fastify CLI.

Install

To install Fastify in an existing project as a dependency:

npm i fastify

Example

// Require the framework and instantiate it

// ESM
import Fastify from 'fastify'

const fastify = Fastify({
  logger: true
})
// CommonJS
const fastify = require('fastify')({
  logger: true
})

// Declare a route
fastify.get('/', (request, reply) => {
  reply.send({ hello: 'world' })
})

// Run the server!
fastify.listen({ port: 3000 }, (err, address) => {
  if (err) throw err
  // Server is now listening on ${address}
})

With async-await:

// ESM
import Fastify from 'fastify'

const fastify = Fastify({
  logger: true
})
// CommonJS
const fastify = require('fastify')({
  logger: true
})

fastify.get('/', async (request, reply) => {
  reply.type('application/json').code(200)
  return { hello: 'world' }
})

fastify.listen({ port: 3000 }, (err, address) => {
  if (err) throw err
  // Server is now listening on ${address}
})

Do you want to know more? Head to the Getting Started.
If you learn best by reading code, explore the official demo.

> ## Note
> .listen binds to the local host, localhost, interface by default
> (127.0.0.1 or ::1, depending on the operating system configuration). If
> you are running Fastify in a container (Docker,
> GCP, etc.), you may need to bind to 0.0.0.0. Be
> careful when listening on all interfaces; it comes with inherent
> [security
> risks](https://web.archive.org/web/20170711105010/https://snyk.io/blog/mongodb-hack-and-secure-defaults/).
> See the documentation for more
> information.

Core features

• Highly performant: as far as we know, Fastify is one of the fastest web

frameworks in town, depending on the code complexity we can serve more than 76
thousand requests per second.

• Extensible: Fastify is fully extensible via its hooks, plugins, and

decorators.

• Schema-based: even if it is not mandatory we recommend using [JSON

Schema](https://json-schema.org/) to validate your routes and serialize your
outputs. Internally Fastify compiles the schema in a highly performant
function.

• Logging: logs are extremely important, but are costly; we chose the best

logger to almost remove this cost, Pino!

• Developer friendly: the framework is built to be very expressive and help

developers in their daily use without sacrificing performance and
security.

Benchmarks

__Machine:__ EX41S-SSD, Intel Core i7, 4Ghz, 64GB RAM, 4C/8T, SSD.

__Method__: autocannon -c 100 -d 40 -p 10 localhost:3000 * 2, taking the
second average

These benchmarks were taken using https://github.com/fastify/benchmarks. This is
a synthetic "hello world" benchmark that aims to evaluate the framework overhead.
The overhead that each framework has on your application depends on your
application. You should __always__ benchmark if performance matters to you.

Documentation

• __<code class="ra0-md-code">Getting Started</code>__
• __<code class="ra0-md-code">Guides</code>__
• __<code class="ra0-md-code">Server</code>__
• __<code class="ra0-md-code">Routes</code>__
• __<code class="ra0-md-code">Encapsulation</code>__
• __<code class="ra0-md-code">Logging</code>__
• __<code class="ra0-md-code">Middleware</code>__
• __<code class="ra0-md-code">Hooks</code>__
• __<code class="ra0-md-code">Decorators</code>__
• __<code class="ra0-md-code">Validation and Serialization</code>__
• __<code class="ra0-md-code">Fluent Schema</code>__
• __<code class="ra0-md-code">Lifecycle</code>__
• __<code class="ra0-md-code">Reply</code>__
• __<code class="ra0-md-code">Request</code>__
• __<code class="ra0-md-code">Errors</code>__
• __<code class="ra0-md-code">Content Type Parser</code>__
• __<code class="ra0-md-code">Plugins</code>__
• __<code class="ra0-md-code">Testing</code>__
• __<code class="ra0-md-code">Benchmarking</code>__
• __<code class="ra0-md-code">How to write a good plugin</code>__
• __<code class="ra0-md-code">Plugins Guide</code>__
• __<code class="ra0-md-code">HTTP2</code>__
• __<code class="ra0-md-code">Long Term Support</code>__
• __<code class="ra0-md-code">TypeScript and types support</code>__
• __<code class="ra0-md-code">Serverless</code>__
• __<code class="ra0-md-code">Recommendations</code>__

Ecosystem

• Core - Core plugins maintained by the

_Fastify_ team.

• Community - Community-supported

plugins.

• Live Examples - Multirepo with a broad

set of real working examples.

• Discord - Join our discord server and

chat with the maintainers.

Support

Please visit Fastify help to view prior
support issues and to ask new support questions.

Version 3 of Fastify and lower are EOL and will not receive any security or bug
fixes.

Fastify's partner, HeroDevs, provides commercial security fixes for all
unsupported versions at [https://herodevs.com/support/fastify-nes][hd-link].
Fastify's supported version matrix is available in the
[Long Term Support][lts-link] documentation.

Contributing

Whether reporting bugs, discussing improvements and new ideas, or writing code,
we welcome contributions from anyone and everyone. Please read the CONTRIBUTING
guidelines before submitting pull requests.

Team

_Fastify_ is the result of the work of a great community. Team members are
listed in alphabetical order.

Lead Maintainers:

• __Matteo Collina__,

,

• __Tomas Della Vedova__,

,

• __KaKa Ng__,

• __Manuel Spigolon__,

,

• __James Sumners__,

,

Fastify Core team

• __Aras Abbasi__,

• __Harry Brundage__,

,

• __Matteo Collina__,

,

• __Gürgün Dayıoğlu__,

• __Tomas Della Vedova__,

,

• __Carlos Fuentes__,

,

• __Vincent Le Goff__
• __Luciano Mammino__,

,

• __Jean Michelet__,

• __KaKa Ng__,

• __Luis Orbaiceta__,

• __Maksim Sinik__,

,

• __Manuel Spigolon__,

,

• __James Sumners__,

,

Fastify Plugins team

• __Harry Brundage__,

,

• __Simone Busoli__,

,

• __Dan Castillo__,

• __Matteo Collina__,

,

• __Gürgün Dayıoğlu__,

• __Tomas Della Vedova__,

,

• __Carlos Fuentes__,

,

• __Vincent Le Goff__
• __Jean Michelet__,

• __KaKa Ng__,

• __Maksim Sinik__,

,

• __Frazer Smith__,
• __Manuel Spigolon__,

,

• __Antonio Tripodi__,

Emeritus Contributors

Great contributors to a specific area of the Fastify ecosystem will be invited
to join this group by Lead Maintainers when they decide to step down from the
active contributor's group.

• __Tommaso Allevi__,

,

• __Ethan Arrowood__,

,

• __Çağatay Çalı__,

,

• __David Mark Clements__,

,

• __dalisoft__, ,

• __Dustin Deus__,

,

• __Denis Fäcke__,

,

• __Rafael Gonzaga__,

,

• __Trivikram Kamat__,

,

• __Ayoub El Khattabi__,

,

• __Cemre Mengu__,

,

• __Salman Mitha__,

• __Nathan Woltman__,

,

Hosted by

<img src="https://raw.githubusercontent.com/openjs-foundation/artwork/main/openjs_foundation/openjs_foundation-logo-horizontal-color.png" width="250px;" />

We are an [At-Large
Project](https://github.com/openjs-foundation/cross-project-council/blob/HEAD/PROJECT_PROGRESSION.md#at-large-projects)
in the OpenJS Foundation.

Sponsors

Support this project by becoming a SPONSOR!
Fastify has an Open Collective
page where we accept and manage financial contributions.

Acknowledgments

This project is kindly sponsored by:

• NearForm
• Platformatic

This list includes all companies that support one or more team members
in maintaining this project.

License

Licensed under MIT.

For your convenience, here is a list of all the licenses of our production
dependencies:

• MIT
• ISC
• BSD-3-Clause
• BSD-2-Clause

[hd-link]: https://www.herodevs.com/support/fastify-nes?utm_source=fastify&utm_medium=link&utm_campaign=github_readme
[lts-link]: https://fastify.dev/docs/latest/Reference/LTS/