Vercel Deployment

Deploy and configure a project on Vercel. If target specifies a particular concern (domains, env vars, etc.), focus there. Otherwise, do the full setup.

Step 1: Install and Authenticate

pnpm add -g vercel
vercel login

If already installed, verify with vercel --version.

Step 2: Link the Project

From the project root:

vercel link

Follow the prompts to connect to an existing Vercel project or create a new one. This creates a .vercel/ directory locally (already in .gitignore by default).

Step 3: Configure vercel.json

Create vercel.json in the project root only if you need non-default settings. Next.js projects usually need minimal config.

{
  "framework": "nextjs",
  "buildCommand": "pnpm build",
  "installCommand": "pnpm install",
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        { "key": "X-Content-Type-Options", "value": "nosniff" },
        { "key": "X-Frame-Options", "value": "DENY" },
        { "key": "Referrer-Policy", "value": "strict-origin-when-cross-origin" }
      ]
    }
  ],
  "redirects": [],
  "rewrites": []
}

Field	When to set
framework	Auto-detected for Next.js. Set explicitly if detection fails.
buildCommand	Override if using a monorepo or custom build step
installCommand	Override if not using npm (e.g., pnpm install)
headers	Add security headers, CORS, caching
redirects	Domain migrations, URL restructuring
rewrites	Proxy API routes, SPA fallbacks
regions	Pin serverless functions to specific regions (e.g., ["iad1"])

Step 4: Environment Variables

Set via CLI

# Add for all environments
vercel env add NEXT_PUBLIC_APP_URL

# Add for specific environments
vercel env add DATABASE_URL production
vercel env add DATABASE_URL preview
vercel env add DATABASE_URL development

Environment Types

Environment	When used	Notes
Production	Main branch deploys	Use production database, real API keys
Preview	PR and branch deploys	Use staging database, test API keys
Development	vercel dev locally	Mirrors .env.local

Pull env vars to local

vercel env pull .env.local

This syncs your Vercel development env vars to .env.local. Never commit this file.

Common env var issues

Problem	Fix
Env var not available at build time	Ensure it's set for the correct environment (Production/Preview)
Client-side var is undefined	Prefix with NEXT_PUBLIC_
Changed env var, still old value	Redeploy. Env vars are baked in at build time.
Secret leaking to client	Remove NEXT_PUBLIC_ prefix. Only server code can access non-prefixed vars.

Step 5: Custom Domains

Add a domain

vercel domains add yourdomain.com

Configure DNS

Vercel provides DNS records to set. Common patterns:

Record type	Name	Value	Use case
A	@	76.76.21.21	Root domain
CNAME	www	cname.vercel-dns.com	www subdomain
CNAME	app	cname.vercel-dns.com	Custom subdomain

Redirect www to root (or vice versa)

Configure in Vercel Dashboard > Domains, or in vercel.json:

{
  "redirects": [
    {
      "source": "/:path((?!api/).*)",
      "has": [{ "type": "host", "value": "www.yourdomain.com" }],
      "destination": "https://yourdomain.com/:path",
      "permanent": true
    }
  ]
}

Step 6: Build Settings

Framework presets

Vercel auto-detects Next.js. Override only when needed:

Setting	Default (Next.js)	Override when
Build command	next build	Monorepo, custom scripts
Output directory	.next	Never change for Next.js
Install command	npm install	Using pnpm or yarn
Root directory	/	Monorepo (set to app directory)
Node.js version	20.x	Need specific version

Monorepo setup

Set the root directory in Vercel project settings to the app's subdirectory:

Root Directory: apps/web

Or use vercel.json at the repo root:

{
  "ignoreCommand": "npx turbo-ignore"
}

Step 7: Preview Deployments

Every push to a non-production branch creates a preview deployment automatically.

Branch-based previews

• Each PR gets a unique URL: <project>-<branch>-<team>.vercel.app
• Comment bots post the preview URL on PRs
• Preview deployments use "Preview" environment variables

Protect preview deployments

In Vercel Dashboard > Settings > General > Password Protection, enable password or Vercel Authentication for preview URLs.

Skip deployments for non-code changes

Add to vercel.json:

{
  "ignoreCommand": "git diff --quiet HEAD^ HEAD -- . ':!docs' ':!*.md'"
}

Step 8: Serverless and Edge Functions

Serverless function config

Next.js API routes and Server Actions deploy as serverless functions by default.

Set runtime and region in the route file:

export const runtime = 'nodejs' // or 'edge'
export const maxDuration = 30   // seconds (default 10, max depends on plan)
export const preferredRegion = 'iad1'

Edge vs. Serverless

Feature	Serverless (nodejs)	Edge (edge)
Cold start	~250ms	~0ms
Runtime	Full Node.js	V8 (limited APIs)
Max duration	10-300s (plan-dependent)	30s
Use for	Database queries, heavy computation	Auth, redirects, geolocation
Node APIs	Full	Subset (no fs, limited crypto)

Step 9: Deploy

Preview deploy (from any branch)

vercel

Production deploy

vercel --prod

Via Git (recommended)

Connect the Git repo in Vercel Dashboard. Every push to main auto-deploys to production. Every PR branch gets a preview.

Troubleshooting

Problem	Cause	Fix
Build fails with module not found	Missing dependency	Check package.json. Run pnpm install and retry.
Build fails with type errors	TypeScript strict mode	Fix type errors locally first: pnpm build
404 on dynamic routes	Missing generateStaticParams or wrong config	Add export const dynamic = 'force-dynamic' or implement generateStaticParams
API route returns 500	Unhandled error or missing env var	Check Vercel function logs: vercel logs <url>
Slow cold starts	Large function bundle	Reduce dependencies. Use edge runtime where possible.
CORS errors	Missing headers	Add CORS headers in vercel.json or middleware
Deployment stuck	Build queue	Cancel and retry: vercel --force

Deployment Checklist

Task	Status
Vercel CLI installed and authenticated
Project linked with vercel link
vercel.json configured (if needed)
Env vars set for Production, Preview, Development
Custom domain added and DNS configured
SSL certificate provisioned (automatic)
Preview deployments working on PRs
vercel --prod deploys successfully
Security headers configured
Function regions set (if latency-sensitive)