agent/.agent/skills/tech-stack/elysiajs/integrations/expo.md

Expo Integration

Run Elysia on Expo (React Native)

What It Is

Create API routes in Expo app (SDK 50+, App Router v3).

Setup

1. Create app/[...slugs]+api.ts
2. Define Elysia server
3. Export Elysia.fetch as HTTP methods

// 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

Prefix for Non-Root

If placed in app/api/[...slugs]+api.ts, set prefix:

const app = new Elysia({ prefix: '/api' })
  .get('/', 'Hello Expo')

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

Ensures routing works in any location.

Eden (End-to-End Type Safety)

1. Export type:

// app/[...slugs]+api.ts
const app = new Elysia()
  .get('/', 'Hello Nextjs')
  .post('/user', ({ body }) => body, {
    body: treaty.schema('User', { name: 'string' })
  })

export type app = typeof app

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

2. Create client:

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

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

3. Use in 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

• Deploy as normal Elysia app OR
• Use experimental Expo server runtime

With Expo runtime:

expo export
# Creates dist/server/_expo/functions/[...slugs]+api.js

Edge function, not normal server (no port allocation).

Adapters

• Express
• Netlify
• Vercel

pnpm

Manual install:

pnpm add @sinclair/typebox openapi-types