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Ergonomic Framework for Humans

TypeScript with End-to-End Type Safety, type integrity, and exceptional developer experience. Supercharged by Bun.

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See why developers love Elysia

The first production ready,
and most loved Bun framework

Our Principle

Design for Humans

Our goal is to design an ergonomic, sensible, and productive framework that even beginners can use easily

Designed to avoid unnecessary complexity and type complexity for you to focus on building

A framework that feels just like JavaScript

typescript
import { Elysia } from 'elysia'

new Elysia()
	.get('/', 'Hello World')
	.get('/image', Bun.file('mika.webp'))
	.get('/stream', function* () {
		yield 'Hello'
		yield 'World'
	})
	.ws('/realtime', {
		message(ws, message) {
			ws.send('got:' + message)
		}
	})
	.listen(3000)

Just return

A string, number, or complex JSON

All we need to do is return

File support built-in

To send a file or image, just return

Nothing more or less

Stream response

Use yield to stream a response

All we need to do is return

Data in real-time

With µWebSocket built-in

Send live data in just 3 lines

The Next Level of Type Safety

typescript
import { 
Elysia
} from 'elysia'
new
Elysia
()
.
get
('/id/:id', ({
params
,
set
}) => {
set
.
headers
.a
return 'Su' }) .
get
('/optional/:name?', ({
params
: {
name
} }) => {
return
name
?? 'Pardofelis'
}) .
listen
(3000)

Your own documentation in 1 line

It's not magic

With deep integration with OpenAPI schema
Elysia can generate Swagger documentation for your API out of the box

Scalar documentation generated by Elysia using Elysia Swagger plugin
typescript
import { Elysia } from 'elysia'
import swagger from '@elysiajs/swagger'

new Elysia()
	.use(swagger())
	.use(character)
	.use(auth)
	.listen(3000)

11.88ms

POST /character/:id/chat

Playback

Request
Validation
Transaction
Upload
Sync
For DevOps

OpenTelemetry

Elysia has 1st party support for OpenTelemetry. Instrumentation is built-in, so you can easily monitor your services on regardless of the platform.

typescript
import { 
treaty
} from '@elysiajs/eden'
import type {
App
} from './server'
const
api
=
treaty
<
App
>('api.elysiajs.com')
const {
data
} = await
api
.
profile
.
patch
({
age
: 21
})
For Frontend

End-to-end Type Safety

Like tRPC, Elysia provides type-safety from the backend to the frontend without code generation. The interaction between frontend and backend is type-checked at compile time.

21x

faster than Express

6x

faster than Fastify

  1. Elysia Bun
    2,454,631 reqs/s
  2. Gin Go

    676,019

  3. Spring Java

    506,087

  4. Fastify Node

    415,600

  5. Express Node

    113,117

  6. Nest Node

    105,064

Measured in requests/second. Result from TechEmpower Benchmark Round 22 (2023-10-17) in PlainText

Test with Confidence

Type safe with auto-completion

Elysia provides a type-safe layer to interact with and test your server, from routes to parameters.

With auto-completion, you can easily write tests for the server without any hassle.

typescript
import { 
treaty
} from '@elysiajs/eden'
import {
app
} from './index'
import {
test
,
expect
} from 'bun:test'
const
server
=
treaty
(
app
)
test
('should handle duplicated user', async () => {
const {
error
} = await
server
.
user
.
put
({
Argument of type '{ username: string; }' is not assignable to parameter of type '{ username: string; password: string; }'. Property 'password' is missing in type '{ username: string; }' but required in type '{ username: string; password: string; }'.
username
: 'mika',
})
expect
(
error
?.
value
).
toEqual
({
success
: false,
message
: 'Username already taken'
}) })

Powered by love
from the community

Made possible by you

Elysia is not owned by an organization, but is driven by the community.
Elysia development is only possible thanks to your support.

Thank you for making Elysia possible

To summarize
Only the best
for the bold

For builders, inventors, and visionaries
We spent years studying the strengths and weaknesses of JavaScript frameworks, all to deliver an exceptional experience

At the speed of light

Up to 21x faster than Express

Supercharged by Bun,

Elysia is one of top performing JavaScript frameworks

Maximum Type Safety

Dynamic type safety

Built from type to runtime

Elysia learns from your codebase, adapts, and enforces your types

Productive in a reach

The best experience of today

Ergonomically designed for humans, prioritizing DX. No technical nonsense

These are the pillars we built Elysia upon,
to deliver the best experience yet

Build the future,
together

Get startedTutorial

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