H3 is a minimal h(ttp) framework built for high performance and portability

✔️  Portable: Works perfectly in Serverless, Workers, and Node.js

✔️  Minimal: Small and tree-shakable

✔️  Modern: Native promise support

✔️  Extendable: Ships with a set of composable utilities but can be extended

✔️  Router: Super fast route matching using unjs/radix3

✔️  Compatible: Compatibility layer with node/connect/express middleware

# Using npm
npm install h3

# Using yarn
yarn add h3

# Using pnpm
pnpm add h3

import { createServer } from "node:http";
import { createApp, eventHandler, toNodeListener } from "h3";

const app = createApp();
app.use(
  "/",
  eventHandler(() => "Hello world!")
);

createServer(toNodeListener(app)).listen(process.env.PORT || 3000);

Example using listhen for an elegant listener:

import { createApp, eventHandler, toNodeListener } from "h3";
import { listen } from "listhen";

const app = createApp();
app.use(
  "/",
  eventHandler(() => "Hello world!")
);

listen(toNodeListener(app));

The app instance created by h3 uses a middleware stack (see how it works) with the ability to match route prefix and apply matched middleware.

To opt-in using a more advanced and convenient routing system, we can create a router instance and register it to app instance.

import { createApp, eventHandler, createRouter } from "h3";

const app = createApp();

const router = createRouter()
  .get(
    "/",
    eventHandler(() => "Hello World!")
  )
  .get(
    "/hello/:name",
    eventHandler((event) => `Hello ${event.context.params.name}!`)
  );

app.use(router);

Tip: We can register same route more than once with different methods.

Routes are internally stored in a Radix Tree and matched using unjs/radix3.

// Handle can directly return object or Promise<object> for JSON response
app.use('/api', eventHandler((event) => ({ url: event.node.req.url }))

// We can have better matching other than quick prefix match
app.use('/odd', eventHandler(() => 'Is odd!'), { match: url => url.substr(1) % 2 })

// Handle can directly return string for HTML response
app.use(eventHandler(() => '<h1>Hello world!</h1>'))

// We can chain calls to .use()
app.use('/1', eventHandler(() => '<h1>Hello world!</h1>'))
   .use('/2', eventHandler(() => '<h1>Goodbye!</h1>'))

// Legacy middleware with 3rd argument are automatically promisified
app.use(fromNodeMiddleware((req, res, next) => { req.setHeader('x-foo', 'bar'); next() }))

// Lazy loaded routes using { lazy: true }
app.use('/big', () => import('./big-handler'), { lazy: true })

H3 has concept of compasable utilities that accept event (from eventHandler((event) => {})) as their first argument. This has several performance benefits over injecting them to event or app instances and global middleware commonly used in Node.js frameworks such as Express, which Only required code is evaluated and bundled and rest of utils can be tree-shaken when not used.

• readRawBody(event, encoding?)
• readBody(event)
• parseCookies(event)
• getCookie(event, name)
• setCookie(event, name, value, opts?)
• deleteCookie(event, name, opts?)
• getQuery(event)
• getRouterParams(event)
• send(event, data, type?)
• sendRedirect(event, location, code=302)
• getRequestHeaders(event, headers) (alias: getHeaders)
• getRequestHeader(event, name) (alias: getHeader)
• setResponseHeaders(event, headers) (alias: setHeaders)
• setResponseHeader(event, name, value) (alias: setHeader)
• appendResponseHeaders(event, headers) (alias: appendHeaders)
• appendResponseHeader(event, name, value) (alias: appendHeader)
• writeEarlyHints(event, links, callback)
• sendStream(event, data)
• sendError(event, error, debug?)
• getMethod(event, default?)
• isMethod(event, expected, allowHead?)
• assertMethod(event, expected, allowHead?)
• createError({ statusCode, statusMessage, data? })
• sendProxy(event, { target, headers?, fetchOptions?, fetch?, sendStream? })
• proxyRequest(event, { target, headers?, fetchOptions?, fetch?, sendStream? })
• sendNoContent(event, code = 204)
• setResponseStatus(event, status)
• getResponseStatus(event)
• getResponseStatusText(event)
• readMultipartFormData(event)

👉 You can learn more about usage in JSDocs Documentation.

You can use more h3 event utilities made by the community.

Please check their READMEs for more details.

PRs are welcome to add your packages.

• h3-cors
  • defineCorsEventHandler(options)
  • isPreflight(event)
• h3-typebox
  • validateBody(event, schema)
  • validateQuery(event, schema)
• h3-zod
  • useValidatedBody(event, schema)
  • useValidatedQuery(event, schema)

MIT