Vercel Deployment Skill

Skill Type: Deployment Management For Agent: @deploy-owner Platform: Vercel (Frontend Hosting)

Skill Purpose

This skill enables Vercel deployment management for React/Next.js frontends including project configuration, environment variables, domain management, and build optimization.

Core Capabilities

1. Vercel CLI Commands

Login & Project Setup:

bash

# Login to Vercel
vercel login

# Link to existing project
vercel link

# Check current project
vercel ls

Deployment:

bash

# Deploy to preview (staging)
vercel

# Deploy to production
vercel --prod

# Deploy specific directory
vercel ./frontend --prod

# Check deployment status
vercel ls

Environment Variables:

bash

# Add environment variable
vercel env add [KEY]

# List all environment variables
vercel env ls

# Pull environment variables to .env.local
vercel env pull

# Remove environment variable
vercel env rm [KEY]

Domain Management:

bash

# List domains
vercel domains ls

# Add domain
vercel domains add [domain]

# Remove domain
vercel domains rm [domain]

Logs & Monitoring:

bash

# View deployment logs
vercel logs [deployment-url]

# List recent deployments
vercel ls

# Inspect deployment
vercel inspect [deployment-url]

2. Vercel Project Structure

Typical React Frontend:

•Framework: React + Vite (or Next.js)
•Build Command: npm run build or yarn build
•Output Directory: dist (Vite) or .next (Next.js)
•Install Command: npm install or yarn install

Environment Variables to Configure:

•VITE_API_URL - Backend API URL (Railway service)
•VITE_ENVIRONMENT - development, staging, or production
•VITE_ANTHROPIC_API_KEY - (if frontend calls Claude directly)

Vercel Environment Scopes:

•Production - Main branch deployments
•Preview - Feature branch deployments
•Development - Local development

3. Deployment Workflow

Standard Deployment Process:

•Ensure code is pushed to git (Vercel auto-deploys from git)
•Verify environment variables are set for target environment
•Check Vercel dashboard for deployment status
•Monitor build logs for errors
•Verify deployment URL loads correctly
•Test critical frontend features
•Verify API calls to backend work (CORS check)
•Monitor for 10+ minutes post-deployment

Branch to Environment Mapping:

•development branch → Preview deployment
•staging branch → Staging/Preview deployment
•main branch → Production deployment

Project Domain Defaults (fill in from codex/PROJECT_CONTEXT.md):

•Marketing site: {{MARKETING_URL}}
•App UI: {{APP_UI_URL}}
•Staging: {{STAGING_UI_URL}}

Domain Guardrails (project-specific):

•Document which domains map to which Vercel projects.
•Document DNS requirements (A/CNAME) and registrar details.
•Use vercel domains inspect <domain> before changes.

Status Snapshot (optional):

•Add current assignment/alias notes here.

Known Build Pitfalls (Project-Specific)

•Add project-specific build pitfalls here.

4. Vercel Configuration Files

vercel.json (at project root):

json

{
  "buildCommand": "npm run build",
  "outputDirectory": "dist",
  "framework": "vite",
  "rewrites": [
    {
      "source": "/(.*)",
      "destination": "/index.html"
    }
  ],
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        {
          "key": "X-Content-Type-Options",
          "value": "nosniff"
        },
        {
          "key": "X-Frame-Options",
          "value": "DENY"
        },
        {
          "key": "X-XSS-Protection",
          "value": "1; mode=block"
        }
      ]
    }
  ]
}

vite.config.ts (for React + Vite):

typescript

import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'

export default defineConfig({
  plugins: [react()],
  build: {
    outDir: 'dist',
    sourcemap: true
  },
  server: {
    port: 3000
  }
})

5. Health Check Protocol

After Every Deployment:

bash

# Check deployment status
vercel ls

# Test deployment URL
curl https://[deployment-url]

# Test API integration
# Open browser DevTools, check Network tab for backend calls

Health Check Success Criteria:

•✅ Deployment status shows "Ready"
•✅ Homepage loads without errors
•✅ No console errors in browser DevTools
•✅ API calls to backend succeed (check Network tab)
•✅ Assets load correctly (CSS, JS, images)
•✅ Routing works (SPA routing via rewrites)

6. Troubleshooting Guide

Common Issues:

Issue: Build fails with "Module not found"

•Check: package.json has all dependencies
•Check: No TypeScript errors
•Check: Import paths are correct (case-sensitive on Vercel)
•Solution: Fix imports, commit, Vercel auto-redeploys

Issue: "404 Not Found" on page refresh

•Check: vercel.json has rewrite rules for SPA routing
•Solution: Add rewrite rule "source": "/(.*)", "destination": "/index.html"

Issue: Environment variables not working

•Check: Variables are set in correct environment (Production/Preview)
•Check: Variable names use correct prefix (VITE_ for Vite, NEXT_PUBLIC_ for Next.js)
•Check: Variables are exposed to browser (only VITE_* or NEXT_PUBLIC_*)
•Solution: Update variables, trigger redeploy

Issue: CORS errors when calling backend

•Check: Backend CORS_ORIGINS includes Vercel domain
•Check: Backend is deployed and running
•Check: API URL is correct in frontend env vars
•Solution: Update backend CORS config, redeploy backend

Issue: Build exceeds time limit

•Check: Build command is optimized
•Check: No unnecessary dependencies
•Solution: Optimize build, remove unused packages

Issue: Assets not loading (404 for CSS/JS)

•Check: Build output directory is correct (dist vs .next)
•Check: Asset paths in HTML are relative, not absolute
•Solution: Update build config, fix asset paths

7. Rollback Procedure

If Deployment Fails:

•Check Vercel dashboard for failed deployment
•Review build logs
•If critical: Use Vercel instant rollback
•Or revert git commit and push

Vercel Instant Rollback:

bash

# List recent deployments
vercel ls

# Promote previous deployment to production
vercel promote [previous-deployment-url] --prod

Git Rollback:

bash

git revert [bad-commit-hash]
git push origin [branch-name]
# Vercel will auto-deploy the revert

Vercel-Specific Best Practices

•Use environment variables - Never hardcode API URLs or secrets
•Enable automatic deployments - Faster than manual CLI
•Use preview deployments - Test on every PR
•Set up custom domains - Professional URLs
•Monitor analytics - Vercel provides Core Web Vitals
•Optimize images - Use Vercel Image Optimization (if Next.js)
•Configure caching - Set appropriate cache headers
•Security headers - Add in vercel.json

Integration with Other Tools

With Railway (Backend):

•Ensure frontend VITE_API_URL points to Railway domain
•Backend must allow Vercel domain in CORS
•Keep frontend/backend deployments synchronized

With Git:

•Vercel watches git branches for changes
•Push to branch → Automatic deployment
•Preview deployments for every PR

With GitHub:

•
Vercel GitHub integration provides:
- •Deployment comments on PRs
- •Preview URLs for every commit
- •Build status checks

Vercel Dashboard Features

Key Sections:

•Deployments - View all deployments, logs, and status
•Environment Variables - Manage env vars per environment
•Domains - Configure custom domains and SSL
•Analytics - View Web Vitals and usage stats
•Settings - Project configuration and integrations

URLs:

•Dashboard: https://vercel.com/dashboard
•Project: https://vercel.com/[team]/[project]
•Deployments: https://vercel.com/[team]/[project]/deployments

Performance Optimization

Vercel Edge Network:

•Automatic global CDN
•Edge caching for static assets
•Brotli/Gzip compression

Build Optimization:

bash

# Analyze bundle size
npm run build -- --analyze

# Enable minification (usually default)
# Check vite.config.ts or next.config.js

Caching Strategy:

json

{
  "headers": [
    {
      "source": "/assets/(.*)",
      "headers": [
        {
          "key": "Cache-Control",
          "value": "public, max-age=31536000, immutable"
        }
      ]
    }
  ]
}

Success Metrics

Deployment is successful when:

•✅ Vercel dashboard shows "Ready" status
•✅ Deployment URL loads in browser
•✅ No errors in browser console
•✅ API calls to backend succeed
•✅ Routing works correctly (SPA navigation)
•✅ Core Web Vitals are green (LCP < 2.5s, FID < 100ms, CLS < 0.1)
•✅ No 404 errors for assets

Quick Reference

Deploy to production:

bash

vercel --prod

Check deployment status:

bash

vercel ls

Update environment variable:

bash

vercel env add VITE_API_URL
# Enter value when prompted
# Then redeploy to apply

Instant rollback:

bash

vercel ls
vercel promote [previous-url] --prod

Monitor logs:

bash

vercel logs [deployment-url]

Environment-Specific Domains

Production:

•https://claude-code-project-template.vercel.app

Staging:

•https://claude-code-project-template-staging.vercel.app

Preview (per-branch):

•https://claude-code-project-template-[branch].vercel.app

Last Updated: 2025-11-23 Maintained By: @deploy-owner Related Skill: railway-deploy.md

Scripts

•scripts/skill_info.py: Print skill name and description.