Vercel Hello World
Overview
Deploy a minimal project to Vercel with a static page and a serverless API route. Confirms your CLI auth, project structure, and deployment pipeline work end to end.
Prerequisites
- Completed
vercel-install-authsetup - Vercel CLI installed and authenticated
- Node.js 18+
Instructions
Step 1: Create Project Structure
mkdir my-vercel-app && cd my-vercel-app
npm init -yCreate the static landing page:
<!-- public/index.html -->
<!DOCTYPE html>
<html>
<head><title>Hello Vercel</title></head>
<body>
<h1>Hello from Vercel</h1>
<p id="result">Loading...</p>
<script>
fetch('/api/hello')
.then(r => r.json())
.then(d => document.getElementById('result').textContent = d.message);
</script>
</body>
</html>Step 2: Create Serverless API Route
// api/hello.ts
import type { VercelRequest, VercelResponse } from '@vercel/node';
export default function handler(req: VercelRequest, res: VercelResponse) {
res.status(200).json({
message: 'Hello from Vercel Serverless Function!',
timestamp: new Date().toISOString(),
region: process.env.VERCEL_REGION || 'local',
});
}Install the types:
npm install --save-dev @vercel/node typescriptStep 3: Add vercel.json Configuration
{
"rewrites": [
{ "source": "/api/(.*)", "destination": "/api/$1" }
],
"headers": [
{
"source": "/api/(.*)",
"headers": [
{ "key": "Cache-Control", "value": "s-maxage=0, stale-while-revalidate" }
]
}
]
}Step 4: Deploy Preview
# Deploy to a preview URL (not production)
vercel
# Output:
# Vercel CLI 39.x.x
# 🔗 Linked to your-team/my-vercel-app
# 🔍 Inspect: https://vercel.com/your-team/my-vercel-app/xxx
# ✅ Preview: https://my-vercel-app-xxx.vercel.appStep 5: Test the Deployment
# Test static page
curl -s https://my-vercel-app-xxx.vercel.app/ | head -5
# Test API route
curl -s https://my-vercel-app-xxx.vercel.app/api/hello | jq .
# {
# "message": "Hello from Vercel Serverless Function!",
# "timestamp": "2026-03-22T12:00:00.000Z",
# "region": "iad1"
# }Step 6: Promote to Production
# Deploy directly to production
vercel --prod
# Or promote the preview deployment
vercel promote https://my-vercel-app-xxx.vercel.appVercel System Environment Variables
These are available in every function at runtime:
| Variable | Value |
|---|---|
VERCEL | "1" — always set on Vercel |
VERCEL_ENV | "production", "preview", or "development" |
VERCEL_URL | Deployment URL (no protocol) |
VERCEL_REGION | Function region (e.g., iad1) |
VERCEL_GIT_COMMIT_SHA | Git commit hash |
VERCEL_GIT_COMMIT_MESSAGE | Git commit message |
Output
- Static page served from Vercel CDN
- Serverless API route returning JSON at
/api/hello - Preview URL for testing before production
- Production deployment live on your domain
Error Handling
| Error | Cause | Solution |
|---|---|---|
404 NOT_FOUND on /api/hello | File not in api/ directory | Move file to project root api/ folder |
FUNCTION_INVOCATION_FAILED | Runtime error in handler | Check function logs: vercel logs <url> |
BUILD_FAILED | TypeScript compilation error | Run npx tsc --noEmit locally first |
NO_RESPONSE_FROM_FUNCTION | Handler didn't call res.send/json | Ensure all code paths return a response |
FUNCTION_PAYLOAD_TOO_LARGE | Response body > 4.5 MB | Paginate or stream the response |
Resources
Next Steps
Proceed to vercel-local-dev-loop for development workflow setup.