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

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Starting from Expo SDK 50 and App Router v3, Expo lets you define API routes directly inside your Expo project. Because Elysia is WinterTC-compliant, you can use it as the handler for those routes by exporting app.fetch under each HTTP method name.
1

Create a catch-all API route file

Create app/[...slugs]+api.ts in your Expo project.
2

Define your Elysia server and export method handlers

// app/[...slugs]+api.ts
import { Elysia, t } from 'elysia'

const app = new Elysia()
  .get('/', 'hello Expo')
  .post('/', ({ body }) => body, {
    body: t.Object({
      name: t.String()
    })
  })

export const GET = app.fetch
export const POST = app.fetch

​
Route prefix

If you place your Elysia server in a subdirectory (e.g. app/api/[...slugs]+api.ts), set the prefix option to match: 
// app/api/[...slugs]+api.ts
import { Elysia, t } from 'elysia'

const app = new Elysia({ prefix: '/api' })
  .get('/', 'Hello Expo')
  .post('/', ({ body }) => body, {
    body: t.Object({
      name: t.String()
    })
  })

export const GET = app.fetch
export const POST = app.fetch

​
End-to-end type safety with Eden

Add Eden Treaty for full type safety between your Expo app and backend.
1

Export the app type from your API route

// app/[...slugs]+api.ts
import { Elysia } from 'elysia'

const app = new Elysia()
  .get('/', 'Hello Expo')

export type app = typeof app

export const GET = app.fetch
export const POST = app.fetch
2

Create a Treaty client

// lib/eden.ts
import { treaty } from '@elysia/eden'
import type { app } from '../app/[...slugs]+api'

export const api = treaty<app>('localhost:3000/api')
3

Use the client in your components

// app/page.tsx
import { api } from '../lib/eden'

export default async function Page() {
  const message = await api.get()

  return <h1>Hello, {message}</h1>
}

​
Deployment

You can deploy your Expo app with Elysia using the experimental Expo server runtime. Run expo export to produce an optimized build — the Elysia handler will be bundled at dist/server/_expo/functions/[...slugs]+api.js.
Expo functions are treated as Edge functions, not persistent servers. Running the function directly does not allocate a port. Use one of the supported Expo function adapters: Express, Netlify, or Vercel.

​
pnpm peer dependencies

If you use pnpm, install peer dependencies manually: 
pnpm add @sinclair/typebox openapi-types

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