ElysiaJS — An Ergonomic Framework for Humans
If you're a developer who loves TypeScript, hates boilerplate, and wants insane performance without sacrificing developer experience, ElysiaJS is something you should know about. Built on top of Bun, ElysiaJS aims to be the most ergonomic and type-safe backend framework ever created.
What Is ElysiaJS?
ElysiaJS is a backend framework designed for humans. Instead of forcing developers to pick between flexibility, performance, and type safety, Elysia gives you all three. It focuses on:
- Ergonomic APIs – code that looks clean and feels natural
- End-to-End Type Safety – your server and client share the same types
- Speed – built on Bun, it’s faster than Express and Fastify
ElysiaJS = Express + TypeScript + Turbocharged Performance
Why Use ElysiaJS?
Unlike traditional frameworks where routing, validation, and documentation are separate tools, Elysia handles all of it together.
| Feature | ElysiaJS |
| Routing | Simple and intuitive |
| Validation | Built-in and type-safe |
| Performance | Extremely fast via Bun |
| Documentation | Auto-generates OpenAPI |
| Real-Time | Native WebSocket support |
| Client Sync | Types shared via Eden Treaty |
Your First ElysiaJS App
import { Elysia } from 'elysia'
new Elysia()
.get('/', 'Hello World')
.listen(3000)
That's it — your server is running.
import { Elysia, file } from 'elysia'
new Elysia()
.get('/image', file('banner.png'))
.get('/stream', function* () {
yield 'Hello '
yield 'World'
})
.ws('/chat', {
message(ws, msg) {
ws.send("You said: " + msg)
}
})
.listen(3000)
No setup chaos. Just return values — Elysia does the heavy lifting.
Type Safety Without Pain
Elysia treats your schema and types as the single source of truth. Write it once, and Elysia uses it for validation, TypeScript inference, and OpenAPI docs.
import { Elysia, t } from 'elysia'
new Elysia()
.post('/user', ({ body }) => body, {
body: t.Object({
name: t.String(),
age: t.Number()
})
})
Client and Server, Finally in Sync
With @elysiajs/eden, your frontend knows exactly what your backend expects. No mismatched types.
import { treaty } from '@elysiajs/eden'
import type { App } from './server'
const api = treaty('http://localhost:3000')
await api.user.post({ name: "Amandeep", age: 21 })
Performance That Speaks for Itself
Because Elysia runs on Bun, it's extremely fast. Benchmarks show it outperforming:
Perfect for high-traffic APIs, SaaS products, and real-time systems.
Who Should Use ElysiaJS?
- Developers who want Bun-level performance
- People who care about type safety
- Teams tired of redundant schemas and configs
- Anyone building modern APIs
Conclusion
ElysiaJS isn’t just another backend framework — it's a new way to think about server development. It’s fast, elegant, and genuinely fun to use.
If you're building APIs today and want to stay ahead, ElysiaJS is worth exploring.
Official Website: https://elysiajs.com
Elysiajs