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5.4.1 • Public • Published


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Router middleware for koa

  • Express-style routing using app.get, app.put,, etc.
  • Named URL parameters.
  • Named routes with URL generation.
  • Responds to OPTIONS requests with allowed methods.
  • Support for 405 Method Not Allowed and 501 Not Implemented.
  • Multiple route middleware.
  • Multiple routers.
  • Nestable routers.
  • ES7 async/await support (koa-router 7.x).

koa 2.x

See koa-router 7.x for koa 2.x and async/await support.


Install using npm:

npm install koa-router

API Reference

Router ⏏

Kind: Exported class

new Router([opts])

Create a new router.

Param Type Description
[opts] Object
[opts.prefix] String prefix router paths

Example Basic usage:

var app = require('koa')();
var router = require('koa-router')();
router.get('/', function *(next) {...});

router.get|put|post|patch|delete ⇒ Router

Create router.verb() methods, where verb is one of the HTTP verbes such as router.get() or

Match URL patterns to callback functions or controller actions using router.verb(), where verb is one of the HTTP verbs such as router.get() or

  .get('/', function *(next) {
    this.body = 'Hello World!';
  .post('/users', function *(next) {
    // ...
  .put('/users/:id', function *(next) {
    // ...
  .del('/users/:id', function *(next) {
    // ...

Route paths will be translated to regular expressions using path-to-regexp.

Query strings will not be considered when matching requests.

Named routes

Routes can optionally have names. This allows generation of URLs and easy renaming of URLs during development.

router.get('user', '/users/:id', function *(next) {
 // ...
router.url('user', 3);
// => "/users/3"

Multiple middleware

Multiple middleware may be given:

  function *(next) {
    this.user = yield User.findOne(;
    yield next;
  function *(next) {
    // => { id: 17, name: "Alex" }

Nested routers

Nesting routers is supported:

var forums = new Router();
var posts = new Router();
posts.get('/', function *(next) {...});
posts.get('/:pid', function *(next) {...});
forums.use('/forums/:fid/posts', posts.routes(), posts.allowedMethods());
// responds to "/forums/123/posts" and "/forums/123/posts/123"

Router prefixes

Route paths can be prefixed at the router level:

var router = new Router({
  prefix: '/users'
router.get('/', ...); // responds to "/users"
router.get('/:id', ...); // responds to "/users/:id"

URL parameters

Named route parameters are captured and added to ctx.params.

router.get('/:category/:title', function *(next) {
  // => { category: 'programming', title: 'how-to-node' }

Kind: instance property of Router

Param Type Description
path String
[middleware] function route middleware(s)
callback function route callback

router.routes ⇒ function

Returns router middleware which dispatches a route matching the request.

Kind: instance property of Router

router.use([path], middleware, [...]) ⇒ Router

Use given middleware(s) before route callback.

Only runs if any route is matched. If a path is given, the middleware will run for any routes that include that path.

Kind: instance method of Router

Param Type
[path] String
middleware function
[...] function


router.use(session(), authorize());
// use middleware only with given path
router.use('/users', userAuth());

router.prefix(prefix) ⇒ Router

Set the path prefix for a Router instance that was already initialized.

Kind: instance method of Router

Param Type
prefix String



router.allowedMethods([options]) ⇒ function

Returns separate middleware for responding to OPTIONS requests with an Allow header containing the allowed methods, as well as responding with 405 Method Not Allowed and 501 Not Implemented as appropriate.

Kind: instance method of Router

Param Type Description
[options] Object
[options.throw] Boolean throw error instead of setting status and header
[options.notImplemented] Function throw the returned value in place of the default NotImplemented error
[options.methodNotAllowed] Function throw the returned value in place of the default MethodNotAllowed error


var app = koa();
var router = router();

Example with Boom

var app = koa();
var router = router();
var Boom = require('boom');
  throw: true,
  notImplemented: () => new Boom.notImplemented(),
  methodNotAllowed: () => new Boom.methodNotAllowed()

router.redirect(source, destination, code) ⇒ Router

Redirect source to destination URL with optional 30x status code.

Both source and destination can be route names.

router.redirect('/login', 'sign-in');

This is equivalent to:

router.all('/login', function *() {
  this.status = 301;

Kind: instance method of Router

Param Type Description
source String URL or route name.
destination String URL or route name.
code Number HTTP status code (default: 301).

router.route(name) ⇒ Layer | false

Lookup route with given name.

Kind: instance method of Router

Param Type
name String

router.url(name, params) ⇒ String | Error

Generate URL for route. Takes the route name and a map of named params.

router.get('user', '/users/:id', function *(next) {
 // ...
router.url('user', 3);
// => "/users/3"
router.url('user', { id: 3 });
// => "/users/3"

Kind: instance method of Router

Param Type Description
name String route name
params Object url parameters

router.param(param, middleware) ⇒ Router

Run middleware for named route parameters. Useful for auto-loading or validation.

Kind: instance method of Router

Param Type
param String
middleware function


  .param('user', function *(id, next) {
    this.user = users[id];
    if (!this.user) return this.status = 404;
    yield next;
  .get('/users/:user', function *(next) {
    this.body = this.user;
  .get('/users/:user/friends', function *(next) {
    this.body = yield this.user.getFriends();
  // /users/3 => {"id": 3, "name": "Alex"}
  // /users/3/friends => [{"id": 4, "name": "TJ"}]

Router.url(path, params) ⇒ String

Generate URL from url pattern and given params.

Kind: static method of Router

Param Type Description
path String url pattern
params Object url parameters


var url = Router.url('/users/:id', {id: 1});
// => "/users/1"


Please submit all issues and pull requests to the alexmingoia/koa-router repository!


Run tests using npm test.


If you have any problem or suggestion please open an issue here.


npm i ddg.koa-router

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