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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/elysiajs/documentation/llms.txt

Use this file to discover all available pages before exploring further.

Because Elysia implements the WinterTC (Web Interoperability) standard, you can test routes by passing standard Request objects directly to app.handle() without binding to a port. Bun ships with a built-in Jest-compatible test runner that makes this straightforward.

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Basic test with Bun Test

Create test/index.test.ts and use bun:test to drive assertions: 
// test/index.test.ts
import { describe, expect, it } from 'bun:test'
import { Elysia } from 'elysia'

describe('Elysia', () => {
    it('returns a response', async () => {
        const app = new Elysia().get('/', () => 'hi')

        const response = await app
            .handle(new Request('http://localhost/'))
            .then((res) => res.text())

        expect(response).toBe('hi')
    })
})
Run the test suite with: 
bun test
The URL passed to new Request(...) must be a fully qualified URL. Partial paths are not valid.
URLValid
http://localhost/user✅
/user❌

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End-to-end tests with Eden Treaty

Eden Treaty provides a type-safe client that mirrors your Elysia router’s shape. Using it in tests gives you auto-complete on paths and fully typed response bodies without starting a real HTTP server.
1

Install Eden

bun add @elysia/eden
2

Create a treaty client from your app instance

Pass the Elysia instance directly to treaty(). No URL or port is needed.
// test/index.test.ts
import { describe, expect, it } from 'bun:test'
import { Elysia } from 'elysia'
import { treaty } from '@elysia/eden'

const app = new Elysia().get('/hello', 'hi')

const api = treaty(app)
3

Write type-safe assertions

Call routes through the api object. The response data and error fields are automatically typed.
describe('Elysia', () => {
    it('returns a response', async () => {
        const { data, error } = await api.hello.get()

        expect(data).toBe('hi')
    })
})
Eden Treaty infers request and response types directly from the Elysia instance, so TypeScript will catch mismatched body shapes or unexpected status codes at compile time before tests even run.

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Using other test runners

app.handle() accepts any standard Request and returns a standard Response, so you can use Jest or Vitest in place of Bun’s test runner if your project requires it. The same request/response pattern applies regardless of the runner.

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