Deploy a Full‑Stack App to Vercel with MongoDB Atlas (Step‑by‑Step)

This guide shows a clean, reliable way to deploy a full‑stack Next.js app on Vercel with MongoDB Atlas. We focus on the steps that matter for real‑world stability: environment variables, connection reuse, the right runtime, and simple checks to avoid 500 errors after deploy.

What you’ll use

• Next.js (App Router) hosted on Vercel
• MongoDB Atlas (M0 free tier or Serverless)
• Route Handlers or Server Actions for backend logic
• Node.js runtime for any database logic (avoid Edge for Mongoose)

Step 1 — Prepare MongoDB Atlas

• Create a project and an M0 (free) or Serverless cluster in your preferred region.
• Create a database user with a strong password.
• Under Network Access, allow your IP during setup. For development, you can use 0.0.0.0/0 temporarily.
• Copy the SRV connection string (mongodb+srv://…); you’ll add it to Vercel as MONGODB_URI.

Step 2 — Add environment variables in Vercel

• Project → Settings → Environment Variables.
• Add MONGODB_URI = your Atlas SRV connection string.
• Optionally add DB_NAME, NEXT_PUBLIC_SITE_URL, and JWT/secret keys if your app needs them.
• Set for Production and Preview; redeploy to apply.

Step 3 — Ensure the correct runtime

• Use the Node.js runtime for DB code. Avoid the Edge runtime with Mongoose.
• In route handlers, prefer the default (Node) or explicitly set runtime if needed.
• Reuse a single DB connection across invocations to avoid new connections on every request.

Step 4 — Connect GitHub and deploy

• Connect your repo to Vercel for automatic deploys from main.
• First deploy validates env vars, route handlers, and MongoDB connectivity.
• Use Vercel Logs to quickly diagnose 500s or connection timeouts.

Best practices that prevent production issues

• Pool and reuse connections instead of connecting per request.
• Validate inputs on server endpoints to reduce noisy DB traffic.
• Use indexes for frequently queried fields; monitor slow operations in Atlas.
• Store secrets only in Vercel env vars, not in the repo.
• Backups and staging: keep a separate Atlas database for preview deployments.

Common errors and quick fixes

• ECONNREFUSED/timeout: check SRV string, user credentials, and Network Access.
• Edge runtime error: switch the handler to Node.js runtime for Mongoose.
• Too many connections: implement connection reuse and avoid per‑request connect.
• 500 after deploy: confirm MONGODB_URI exists in the Production environment.

FAQs

1. Can I use the free tier? Yes. Start with M0; upgrade when traffic grows.
2. Is Prisma better than Mongoose? Prisma offers a great DX; Mongoose is fine if you prefer schema models. Choose based on your team’s experience.
3. How do I run cron jobs? Use Vercel Cron to hit a protected Route Handler that performs your task against Atlas.
4. How do I seed data? Run a local script against the production URI or a protected one‑off endpoint; remove it after use.
5. Do I need IP allowlists? With SRV + credentials, you typically don’t. Avoid hard‑coding Vercel IPs; rely on SRV DNS and auth.

Need help deploying securely with MongoDB Atlas? I set up production‑ready pipelines, performance monitoring, and backups. Explore services or contact me for a tailored deployment plan.

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