Elysia.js - Ergonomic Framework for Humans

21x faster than Express

Supercharged by the Bun runtime and built-in optimizations such as Static Code Analysis, and Dynamic Code Injection.

Elysia.js one of the most performant TypeScript frameworks, even comparable to solutions written in Go and Rust.

ElysiaBun
2,454,631 req/s
Swoole PHP
1,035,418
Gin Go
676,019
Spring Java
506,087
FastAPI PyPy
448,130
Fastify Node
415,600
Express Node
113,117
Nest Node
105,064

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

Made for Humans

Productivity ++

If you have ever spent more time writing code for the framework instead of your application, then there's something wrong with the framework.

Elysia prioritizes developer experience by experimenting with design decisions to craft the best ergonomics.

Built-in features such as strict type validation, robust type system, and automatic documentation generation, make Elysia an ideal framework for building servers with TypeScript.

typescript

import { Elysia } from 'elysia'

new Elysia()
  .get('/', 'Hello World')
  .get('/json', () => ({ hello: 'world' }))
  .get('/id/:id', ({ params: { id } }) => id)
  .listen(3000)

Just Value

No need for an additional method, just return the value to send data back to the client.

Whether it's a regular string, or complex JSON, just return the value and Elysia will handle the rest

typescript

import { Elysia
, t
 } from 'elysia'

new Elysia
()
  .post
(
    '/profile',
    // ↓ hover me ↓
    ({ body
 }) => body
,
    {
      body
: t
.Object
({
        username
: t
.String
(),
      }),
    },
  )
  .listen
(3000)

Type Safety

Elysia infers types to TypeScript automatically to create unified type system like statically typed language

typescript

import { Elysia, t } from 'elysia'
import { swagger } from '@elysiajs/swagger'
import { users, feed } from './controllers'

new Elysia()
  .use(swagger())
  .use(users)
  .use(feed)
  .listen(3000)

OpenAPI / Swagger

Elysia generates OpenAPI 3.0 specs automatically to integrate with various tools across multiple languages

Thanks to OpenAPI compliance, Elysia can generate Swagger in one line with the Swagger plugin.

End–to-End Type Safety

Synchronize types across all applications.
Move fast and break nothing like tRPC.

Hover code below to see type definition

server.ts

typescript

import { Elysia
, t
 } from 'elysia'

const app
 = new Elysia
()
  .patch
(
    '/user/profile',
    ({ body
, error
 }) => {
      if (body
.age
 < 18) return error
(400, 'Oh no')

      if (body
.name
 === 'Nagisa') return error
(418)

      return body

    },
    {
      body
: t
.Object
({
        name
: t
.String
(),
        age
: t
.Number
(),
      }),
    },
  )
  .listen
(80)

export type App
 = typeof app

client.ts

typescript

import { treaty
 } from '@elysiajs/eden'
import type { App
 } from './server'

const api
 = treaty
<App
>('localhost')

const { data
, error
 } = await api
.user
.profile
.patch
({
  name
: 'saltyaom',
  age: '21',Type 'string' is not assignable to type 'number'.
})

if (error
)
  switch (error
.status
) {
    case 400:
      throw error
.value


    case 418:
      throw error
.value

  }

data