Routing in Elysia is the process of mapping HTTP methods and URL patterns to handler functions. Elysia provides a simple, chainable API for defining routes.
Basic routing Define routes using HTTP method functions like .get(), .post(), .put(), .delete(), and more:
import { Elysia } from 'elysia' const app = new Elysia () . get ( '/' , () => 'Hello World' ) . post ( '/user' , () => 'Create user' ) . put ( '/user/:id' , () => 'Update user' ) . delete ( '/user/:id' , () => 'Delete user' ) . listen ( 3000 )
Route patterns Static routes Static routes match exact paths:
app . get ( '/' , () => 'Root' ) . get ( '/about' , () => 'About' ) . get ( '/contact/info' , () => 'Contact Info' )
Path parameters Capture dynamic segments using the :param syntax:
app . get ( '/id/:id' , ({ params : { id } }) => id ) app . get ( '/user/:id/:name' , ({ params : { id , name } }) => { return `User ${ name } with ID ${ id } ` })
Path parameters are automatically extracted and available in the params object of the context.
Optional parameters Make parameters optional using the ? suffix:
app . get ( '/id/:id?' , ({ params : { id } }) => { return id || 'No ID provided' }) app . get ( '/user/:id?/:name?' , ({ params }) => { const { id = 'unknown' , name = 'anonymous' } = params return `User ${ name } with ID ${ id } ` })
Wildcard routes Match any path segment using the * wildcard:
app . get ( '/public/*' , () => 'Public files' ) app . get ( '/api/*/status' , () => 'Status endpoint' )
HTTP methods Elysia supports all standard HTTP methods:
GET
POST
PUT
DELETE
PATCH
app . get ( '/users' , () => getAllUsers ())
Used for retrieving resources. app . post ( '/users' , ({ body }) => createUser ( body ))
Used for creating resources. app . put ( '/users/:id' , ({ params , body }) => updateUser ( params . id , body ) )
Used for updating resources. app . delete ( '/users/:id' , ({ params }) => deleteUser ( params . id ) )
Used for deleting resources. app . patch ( '/users/:id' , ({ params , body }) => patchUser ( params . id , body ) )
Used for partial updates. Path prefixes Set a prefix for all routes using the prefix configuration:
const app = new Elysia ({ prefix: '/api/v1' }) . get ( '/users' , () => 'Users' ) // /api/v1/users . get ( '/posts' , () => 'Posts' ) // /api/v1/posts
Route grouping Group related routes with a common prefix:
app . group ( '/api' , ( app ) => app . get ( '/users' , () => 'Get users' ) . post ( '/users' , () => 'Create user' ) ) app . group ( '/admin' , ( app ) => app . get ( '/dashboard' , () => 'Dashboard' ) . get ( '/settings' , () => 'Settings' ) )
Query strings Access query parameters through the query object:
app . get ( '/' , ({ query : { id } }) => { return `ID: ${ id } ` }) // GET /?id=123 → "ID: 123" app . get ( '/search' , ({ query }) => { const { q , limit = '10' , offset = '0' } = query return { query: q , limit , offset } }) // GET /search?q=elysia&limit=20 → {"query":"elysia","limit":"20","offset":"0"}
Strict path mode By default, Elysia ignores trailing slashes. Enable strict path matching:
const app = new Elysia ({ strictPath: true }) . get ( '/users' , () => 'Users' ) // Only matches /users . get ( '/posts/' , () => 'Posts' ) // Only matches /posts/
With strictPath: true, /users and /users/ are treated as different routes.
Router history Access all registered routes:
const app = new Elysia () . get ( '/' , () => 'Home' ) . post ( '/users' , () => 'Create' ) console . log ( app . routes ) // [ // { method: 'GET', path: '/', ... }, // { method: 'POST', path: '/users', ... } // ]
Best practices
Use semantic HTTP methods
Follow REST conventions:
GET for readingPOST for creatingPUT for full updatesPATCH for partial updatesDELETE for removing
Keep routes flat and simple
Prefer /users/:id/posts over deeply nested routes like /api/v1/users/:userId/posts/:postId/comments/:commentId.
Use route grouping for organization
Group related routes together to improve code organization and maintainability.
Next steps
Handlers Learn how to write request handlers
Context Understand the context object