AutoGineer summary
Written by AutoGineer from the skill’s own files, not by the author
EAS Hosting provides a managed environment for deploying Expo web bundles and server-side API routes. Built on Cloudflare Workers, this service allows developers to manage environment secrets, custom domains, and server-side logic directly within an Expo project. The skill covers the deployment workflow, API route authoring using standard Web APIs, and integration with cloud-based databases.
What it does
- Deploys Expo web applications and API routes to EAS Hosting
- Supports production and preview deployments via CLI
- Provides guidance on authoring server-side API routes using +api.ts files
- Manages environment variables and secrets for server-side operations
- Configures custom domains and hosting environments
- Offers patterns for request handling, CORS, and authentication middleware
When to use it
- When deploying an Expo web application or API routes
- When you need server-side secrets or database operations hidden from the client
- When creating webhook endpoints or proxying third-party APIs
- When configuring hosting environments and custom domains for Expo projects
Advantages
- Unified deployment for both frontend web bundles and backend API routes
- Native support for Expo Router API route structure
- Integration with EAS CLI for automated deployment workflows
- Standardized environment variable management
- Access to edge-compatible runtime environments
Usage examples
- “How do I deploy my Expo web app to production using EAS Hosting?”
- The agent will guide you to run 'npx expo export -p web' followed by 'eas deploy --prod' to ship your bundle to the managed edge.
- “Create an API route in my Expo project to securely fetch data from an external service.”
- The agent will provide a code example using an 'app/api/route+api.ts' file, demonstrating how to use 'process.env' for secrets and the 'fetch' API.
Install
Download the skill as a ZIP:
https://autogineer.com/agent-skills/expo/eas-hosting/downloadUnzip it into the cross-client skills folder of your project:
mkdir -p .agents/skills && unzip eas-hosting.zip -d .agents/skills
Documentation by Expo
EAS Hosting
EAS service - costs apply. EAS Hosting is a paid Expo Application Services product with free-tier limits; production deploys use your plan's request and bandwidth allowance. See https://expo.dev/pricing. Authoring API routes and exporting the web bundle are free and open source, and you can self-host the exported server output instead of EAS Hosting.
EAS Hosting deploys your Expo web app and API routes to Expo's managed edge (Cloudflare Workers). Export the web bundle with npx expo export -p web and ship it with eas deploy - the same command deploys any Expo Router API routes bundled alongside it. This skill covers deploying a website, authoring API routes, and the hosting runtime; see the Deployment section below for the deploy workflow.
When to Use API Routes
Use API routes when you need:
Server-side secrets — API keys, database credentials, or tokens that must never reach the client
Database operations — Direct database queries that shouldn't be exposed
Third-party API proxies — Hide API keys when calling external services (OpenAI, Stripe, etc.)
Server-side validation — Validate data before database writes
Webhook endpoints — Receive callbacks from services like Stripe or GitHub
Rate limiting — Control access at the server level
Heavy computation — Offload processing that would be slow on mobile
When NOT to Use API Routes
Avoid API routes when:
Data is already public — Use direct fetch to public APIs instead
No secrets required — Static data or client-safe operations
Real-time updates needed — Use WebSockets or services like Supabase Realtime
Simple CRUD — Consider Firebase, Supabase, or Convex for managed backends
File uploads — Use direct-to-storage uploads (S3 presigned URLs, Cloudflare R2)
Authentication only — Use Clerk, Auth0, or Firebase Auth instead
File Structure
API routes live in the app directory with +api.ts suffix:
app/
api/
hello+api.ts → GET /api/hello
users+api.ts → /api/users
users/[id]+api.ts → /api/users/:id
(tabs)/
index.tsxBasic API Route
// app/api/hello+api.ts
export function GET(request: Request) {
return Response.json({ message: "Hello from Expo!" });
}HTTP Methods
Export named functions for each HTTP method:
// app/api/items+api.ts
export function GET(request: Request) {
return Response.json({ items: [] });
}
export async function POST(request: Request) {
const body = await request.json();
return Response.json({ created: body }, { status: 201 });
}
export async function PUT(request: Request) {
const body = await request.json();
return Response.json({ updated: body });
}
export async function DELETE(request: Request) {
return new Response(null, { status: 204 });
}Dynamic Routes
// app/api/users/[id]+api.ts
export function GET(request: Request, { id }: { id: string }) {
return Response.json({ userId: id });
}Request Handling
Query Parameters
export function GET(request: Request) {
const url = new URL(request.url);
const page = url.searchParams.get("page") ?? "1";
const limit = url.searchParams.get("limit") ?? "10";
return Response.json({ page, limit });
}Headers
export function GET(request: Request) {
const auth = request.headers.get("Authorization");
if (!auth) {
return Response.json({ error: "Unauthorized" }, { status: 401 });
}
return Response.json({ authenticated: true });
}JSON Body
export async function POST(request: Request) {
const { email, password } = await request.json();
if (!email || !password) {
return Response.json({ error: "Missing fields" }, { status: 400 });
}
return Response.json({ success: true });
}Environment Variables
Use process.env for server-side secrets:
// app/api/ai+api.ts
export async function POST(request: Request) {
const { prompt } = await request.json();
const response = await fetch("https://api.openai.com/v1/chat/completions", {
method: "POST",
headers: {
"Content-Type": "application/json",
Authorization: `Bearer ${process.env.OPENAI_API_KEY}`,
},
body: JSON.stringify({
model: "gpt-4",
messages: [{ role: "user", content: prompt }],
}),
});
const data = await response.json();
return Response.json(data);
}Set environment variables:
Local: Create
.envfile (never commit)EAS Hosting: Use
eas env:createor Expo dashboard
CORS Headers
Add CORS for web clients:
const corsHeaders = {
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, OPTIONS",
"Access-Control-Allow-Headers": "Content-Type, Authorization",
};
export function OPTIONS() {
return new Response(null, { headers: corsHeaders });
}
export function GET() {
return Response.json({ data: "value" }, { headers: corsHeaders });
}Error Handling
export async function POST(request: Request) {
try {
const body = await request.json();
// Process...
return Response.json({ success: true });
} catch (error) {
console.error("API error:", error);
return Response.json({ error: "Internal server error" }, { status: 500 });
}
}Testing Locally
Start the development server with API routes:
npx expo serveThis starts a local server at http://localhost:8081 with full API route support.
Test with curl:
curl http://localhost:8081/api/hello
curl -X POST http://localhost:8081/api/users -H "Content-Type: application/json" -d '{"name":"Test"}'Deployment to EAS Hosting
Prerequisites
npm install -g eas-cli
eas loginDeploy
Deploying ships your web bundle and any Expo Router API routes together - eas deploy handles both. The export runs whether you have a full website, an API-routes-only backend, or both.
# Export the web bundle (includes any API routes)
npx expo export -p web
# Deploy a preview (PR-style URL)
npx eas-cli@latest deploy
# Deploy to production
npx eas-cli@latest deploy --prodEverything lands on EAS Hosting (Cloudflare Workers).
Environment Variables for Production
# Create a secret
eas env:create --name OPENAI_API_KEY --value sk-xxx --environment production
# Or use the Expo dashboardCustom Domain
Configure in eas.json or Expo dashboard.
Automate with EAS Workflows
Deploy the website (and API routes) on every push to main with a type: deploy workflow:
.eas/workflows/deploy.yml
name: Deploy
on:
push:
branches:
- main
# https://docs.expo.dev/eas/workflows/syntax/#deploy
jobs:
deploy_web:
type: deploy
params:
prod: truePreview deploys for pull requests use the same job type with prod: false:
name: Web PR Preview
on:
pull_request:
types: [opened, synchronize]
jobs:
preview:
type: deploy
params:
prod: falseTo author or validate workflow YAML beyond these examples, use the eas-workflows skill.
EAS Hosting Runtime (Cloudflare Workers)
API routes run on Cloudflare Workers. Key limitations:
Missing/Limited APIs
No Node.js filesystem —
fsmodule unavailableNo native Node modules — Use Web APIs or polyfills
Limited execution time — 30 second timeout for CPU-intensive tasks
No persistent connections — WebSockets require Durable Objects
fetch is available — Use standard fetch for HTTP requests
Use Web APIs Instead
// Use Web Crypto instead of Node crypto
const hash = await crypto.subtle.digest(
"SHA-256",
new TextEncoder().encode("data")
);
// Use fetch instead of node-fetch
const response = await fetch("https://api.example.com");
// Use Response/Request (already available)
return new Response(JSON.stringify(data), {
headers: { "Content-Type": "application/json" },
});Database Options
Since filesystem is unavailable, use cloud databases:
Cloudflare D1 — SQLite at the edge
Turso — Distributed SQLite
PlanetScale — Serverless MySQL
Supabase — Postgres with REST API
Neon — Serverless Postgres
Example with Turso:
// app/api/users+api.ts
import { createClient } from "@libsql/client/web";
const db = createClient({
url: process.env.TURSO_URL!,
authToken: process.env.TURSO_AUTH_TOKEN!,
});
export async function GET() {
const result = await db.execute("SELECT * FROM users");
return Response.json(result.rows);
}Calling API Routes from Client
// From React Native components
const response = await fetch("/api/hello");
const data = await response.json();
// With body
const response = await fetch("/api/users", {
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({ name: "John" }),
});Common Patterns
Authentication Middleware
// utils/auth.ts
export async function requireAuth(request: Request) {
const token = request.headers.get("Authorization")?.replace("Bearer ", "");
if (!token) {
throw new Response(JSON.stringify({ error: "Unauthorized" }), {
status: 401,
headers: { "Content-Type": "application/json" },
});
}
// Verify token...
return { userId: "123" };
}
// app/api/protected+api.ts
import { requireAuth } from "../../utils/auth";
export async function GET(request: Request) {
const { userId } = await requireAuth(request);
return Response.json({ userId });
}Proxy External API
// app/api/weather+api.ts
export async function GET(request: Request) {
const url = new URL(request.url);
const city = url.searchParams.get("city");
const response = await fetch(
`https://api.weather.com/v1/current?city=${city}&key=${process.env.WEATHER_API_KEY}`
);
return Response.json(await response.json());
}Rules
NEVER expose API keys or secrets in client code
ALWAYS validate and sanitize user input
Use proper HTTP status codes (200, 201, 400, 401, 404, 500)
Handle errors gracefully with try/catch
Keep API routes focused — one responsibility per endpoint
Use TypeScript for type safety
Log errors server-side for debugging
Submitting Feedback
If you encounter errors, misleading or outdated information in this skill, report it so Expo can improve:
npx --yes @expo/agent-cli@latest feedback --category skills --subject "eas-hosting" "<actionable feedback>"Only submit when you have something specific and actionable to report. Include as much relevant context as possible.
If an agent repeatedly fails at an Expo task or the user has to step in, submit a brief report of the task, expected result, and what went wrong using --category evals and the relevant Expo package or command as --subject.
Files
- ATTRIBUTION.mdAdded by AutoGineer809 B
- LICENSELicence file added by AutoGineer1.1 KiB
- SKILL.md11.3 KiB
- agents/openai.yaml444 B
LICENSE
The MIT License (MIT) Copyright (c) 2025-present 650 Industries, Inc. (aka Expo) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Requirements and compatibility
Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta
“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.
Needs: Needs network access, Needs an API key, Needs Node.js
Security
What our scanner noticed· Low risk
- Instructions that use the network
A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.
Attribution and licence
- Published by
- Expo
- Publisher
- Expo (Official)
- Source
- expo/skills · plugins/expo/skills/eas-hosting · commit a9e5bd3
- Licence
- MIT License (redistribution allowed)
- LICENSE (added by AutoGineer from plugins/expo/LICENSE)
- ATTRIBUTION.md (written by AutoGineer)
- Synced
AutoGineer is not affiliated with or endorsed by Expo or Expo.
Download ZIP
The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download eas-hosting.zip