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-auth setup
Vercel CLI installed and authenticated
Node.js 18+

Instructions

Step 1: Create Project Structure

mkdir my-vercel-app && cd my-vercel-app
npm init -y

Create 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 typescript

Step 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.app

Step 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.app

Vercel 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

Examples

Deploy a harmless preview before connecting a domain

Create a minimal route that returns a static health response and deploy it with vercel --yes from a feature branch. Test the generated preview URL, verify the commit SHA in the deployment metadata, and keep environment variables absent unless the example requires them. Only after the preview is healthy should a reviewer approve the production workflow; do not point a customer domain at an unreviewed hello-world deployment.

Resources

Next Steps

Proceed to vercel-local-dev-loop for development workflow setup.

vercel-hello-world