Vercel Environment Variables Sync

Esta skill proporciona scripts automatizados, funciones compartidas y patrones completos para gestionar variables de entorno en Vercel. Garantiza sincronización perfecta entre desarrollo local y todos los entornos de deployment.

🎯 When to Use This Skill

•Pre-deployment validation: Ensure all required env vars exist before deploying
•Environment synchronization: Push local .env values to Vercel or pull Vercel vars locally
•Security audits: Auto-detect and mark sensitive variables with --sensitive flag
•Team onboarding: Help new developers get correct environment configuration
•CI/CD integration: Automate env var validation in deployment pipelines
•Multi-environment management: Sync across production, preview, and development

📦 Skill Components

Scripts (`./scripts/`)

•
env-push.sh - Push local vars to Vercel
- •Reads from .env.local and .env with fallback to .env.example
- •Auto-detects sensitive variables (DATABASE_URL, __SECRET, __KEY, etc.)
- •Supports --dry-run, --force, --all-envs flags
- •Uses modern vercel env update instead of deprecated rm + add pattern
•
env-pull.sh - Pull Vercel vars to local file
- •Download env vars from Vercel to .env.local (or custom output)
- •Supports Git branch-specific variables (--branch feature-x)
- •Environment selection: production, preview, or development
•
env-audit.sh - Comprehensive sync status report
- •Compare local .env.example with all Vercel environments
- •Table or JSON output format
- •Shows missing, extra, and synced variables per environment

Libraries (`./lib/`)

•
env-functions.sh - Shared bash functions:
- •vercel::env::set() - Create/update vars with auto --sensitive detection
- •vercel::env::pull() - Pull vars from Vercel
- •vercel::env::validate_value() - Validate var values (URLs, secrets length, etc.)
- •vercel::env::is_sensitive() - Detect sensitive variables
- •vercel::env::health_check() - Verify CLI, auth, and project config
- •Plus 15+ more helper functions

🚀 Quick Start

Installation

bash

# Navigate to workspace root
cd /path/to/project

# Make scripts executable
chmod +x .github/skills/vercel-env-sync/scripts/*.sh
chmod +x .github/skills/vercel-env-sync/lib/*.sh

# Verify Vercel CLI is installed
vercel --version

# Authenticate
vercel login

# Link project
vercel link

Basic Workflow

bash

# Shortcut: navigate to skill directory
cd .github/skills/vercel-env-sync

# 1. Health check
source lib/env-functions.sh
vercel::env::health_check

# 2. Audit current state
./scripts/env-audit.sh

# 3. Push missing variables (dry-run first)
./scripts/env-push.sh --all-envs --dry-run
./scripts/env-push.sh --all-envs

# 4. Pull variables for development
./scripts/env-pull.sh --env development

# 5. Verify sync
./scripts/env-audit.sh

📖 Core Patterns

Pattern 1: Audit Before Deployment

Objetivo: Verify all required variables exist in all environments before deploying.

Workflow:

bash

# Generate audit report
./scripts/env-audit.sh

# Output shows per-environment status:
# Variable                       Production   Preview      Development
# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
# DATABASE_URL                   ✓ Existe    ✓ Existe    ✓ Existe
# NEXT_PUBLIC_APP_URL            ✗ Falta     ✗ Falta     ✗ Falta
# BETTER_AUTH_SECRET             ✗ Falta     ✗ Falta     ✗ Falta

Exit codes:

•0: All variables synced
•1: Missing variables detected (blocks deployment)

Pattern 2: Push Local Vars to Vercel (Modern Approach)

Objetivo: Sync .env.local values to Vercel using best practices.

Script: env-push.sh

Key Improvements Over Legacy Scripts:

•✅ Uses vercel env update instead of rm + add (Vercel CLI v33+)
•✅ Auto-detects sensitive variables and adds --sensitive flag
•✅ Validates values before pushing (URL format, secret length, no placeholders)
•✅ Supports dry-run mode
•✅ Creates automatic backups before modifications

Usage:

bash

# Push to production only (default)
./scripts/env-push.sh

# Push to all environments
./scripts/env-push.sh --all-envs

# Preview changes without applying
./scripts/env-push.sh --all-envs --dry-run

# Force update existing variables
./scripts/env-push.sh --all-envs --force

# Specific environment
./scripts/env-push.sh --env preview

Example Output:

code

🚀 Sincronizando variables de entorno con Vercel...

🏥 Verificación de salud...
  ✓ Vercel CLI instalado
  ✓ Autenticado como: melosdev
  ✓ Proyecto vinculado: wispy-poetry-52762475
  ✓ .env.example existe (4 variables)

🎯 Configuración:
  Entornos: production preview development
  Forzar actualización: false
  Dry run: false
  Backup automático: true

💾 Creando backups...
✓ Backup guardado en .env.backup.production.20260114_153022

📦 Procesando entorno: production
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
📝 Creando DATABASE_URL en production... [SENSITIVE]
✓ DATABASE_URL creado en production

Pattern 3: Pull Variables for Development

Objetivo: Download Vercel env vars to local .env.local for development.

Script: env-pull.sh

Usage:

bash

# Pull development vars to .env.local
./scripts/env-pull.sh

# Pull production vars
./scripts/env-pull.sh --env production

# Pull to custom file
./scripts/env-pull.sh --output .env.ci --env preview

# Pull preview vars for specific Git branch
./scripts/env-pull.sh --env preview --branch feature-auth

# Overwrite without confirmation
./scripts/env-pull.sh --yes

Example:

bash

$ ./scripts/env-pull.sh --env production

⬇️  Descargando variables de entorno desde Vercel...

🎯 Configuración:
  Entorno: production
  Archivo: .env.local

✅ Variables descargadas exitosamente

📁 Archivo: .env.local
📊 Variables: 4

💡 Próximos pasos:
   1. Revisar: cat .env.local
   2. Iniciar dev: vercel env run -- pnpm dev

Pattern 4: Run Commands with Vercel Env (Modern)

Objetivo: Execute commands with Vercel environment variables without writing .env files.

Command: vercel env run (Vercel CLI native feature)

Usage:

bash

# Run dev server with Vercel env vars
vercel env run -- pnpm dev

# Run tests with preview environment
vercel env run -e preview -- pnpm test

# Build with production vars
vercel env run -e production -- pnpm build

# Execute custom script
vercel env run -- node scripts/migrate.js

Why This Pattern?:

•✅ No .env files in repository
•✅ Always uses latest Vercel values
•✅ Works in CI/CD without manual pulls
•✅ Prevents stale local env files

Pattern 5: Validate Values Before Push

Objetivo: Auto-validate environment variable values to prevent invalid configurations.

Built into: env-push.sh via lib/env-functions.sh

Validations Applied:

bash

# Minimum secret length
BETTER_AUTH_SECRET: ≥ 32 characters
NEXTAUTH_SECRET: ≥ 32 characters
*_SECRET: ≥ 32 characters

# URL format
*_URL: Must start with http:// or https://
*_ENDPOINT: Must start with http:// or https://

# PostgreSQL connection string
DATABASE_URL: Must start with postgresql://

# Placeholder detection
Rejects: "your-", "changeme", "placeholder", "example"

Example:

bash

$ vercel::env::validate_value "BETTER_AUTH_SECRET" "short"
❌ BETTER_AUTH_SECRET debe tener al menos 32 caracteres

$ vercel::env::validate_value "API_URL" "not-a-url"
⚠️  API_URL debería ser una URL válida (http:// o https://)

$ vercel::env::validate_value "DATABASE_URL" "mysql://..."
❌ DATABASE_URL debe ser una conexión PostgreSQL válida

Pattern 6: Sensitive Variables Auto-Detection

Objetivo: Automatically mark sensitive variables with --sensitive flag.

Implementation: Built into vercel::env::set() function.

Detection Rules:

•

Hardcoded list (in lib/env-functions.sh):

bash

SENSITIVE_VARS=(
  "DATABASE_URL"
  "BETTER_AUTH_SECRET"
  "NEON_API_KEY"
  "GITHUB_TOKEN"
  "VERCEL_TOKEN"
  "NEXTAUTH_SECRET"
  "API_KEY"
  "API_SECRET"
  "PRIVATE_KEY"
  "SECRET_KEY"
)

•
Pattern matching:
- •Any variable containing: SECRET, PASSWORD, KEY, TOKEN, PRIVATE

Result:

bash

# Automatically adds --sensitive flag
printf "%s\n" "$value" | vercel env add DATABASE_URL production --sensitive

Pattern 7: Automated Backups

Objetivo: Create automatic backups before modifying Vercel env vars.

Usage:

bash

# Manual backup
source lib/env-functions.sh
vercel::env::backup production
# Output: .env.backup.production.20260114_153022

# Automatic (built into env-push.sh)
./scripts/env-push.sh --all-envs
# Creates backups automatically before any changes

Restore from Backup:

bash

# Manual restore
vercel env pull .env.backup.production.20260114_153022
# Review changes
cat .env.backup.production.20260114_153022
# Apply manually if needed

🔧 Advanced Patterns

Pattern 8: CI/CD Integration

GitHub Actions Example:

yaml

name: Verify Environment Variables

on:
  pull_request:
    paths:
      - ".env.example"
  workflow_dispatch:

jobs:
  env-audit:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: "20"

      - name: Install Vercel CLI
        run: npm install -g vercel

      - name: Audit Environment Variables
        env:
          VERCEL_TOKEN: ${{ secrets.VERCEL_TOKEN }}
        run: |
          cd .github/skills/vercel-env-sync
          chmod +x scripts/*.sh lib/*.sh

          # Link project with token
          vercel link --yes --token $VERCEL_TOKEN

          # Run audit
          ./scripts/env-audit.sh --json > audit-result.json

          # Check exit code
          if [ $? -ne 0 ]; then
            echo "❌ Environment variables not synced"
            cat audit-result.json
            exit 1
          fi

      - name: Comment PR
        if: failure()
        uses: actions/github-script@v7
        with:
          script: |
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: '⚠️ Environment variables need sync. Run: `.github/skills/vercel-env-sync/scripts/env-push.sh --all-envs`'
            })

Pattern 9: Git Branch-Specific Variables

Objetivo: Use different env vars for different Git branches (feature branches).

Usage:

bash

# Auto-detect current branch
CURRENT_BRANCH=$(git branch --show-current)

# Pull vars for current branch
./scripts/env-pull.sh --env preview --branch "$CURRENT_BRANCH"

# Run dev with branch-specific vars
vercel env run -e preview --git-branch="$CURRENT_BRANCH" -- pnpm dev

Vercel Setup:

•Go to Vercel Dashboard → Project → Settings → Environment Variables
•Click on variable → Edit → Git Branch → Select specific branch
•Now that variable only applies to deployments from that branch

Pattern 10: JSON Output for Programmatic Use

Objetivo: Generate machine-readable audit reports.

Usage:

bash

# Generate JSON report
./scripts/env-audit.sh --json > env-status.json

# Parse with jq
jq '.local_vars[] | select(.environments.production == false)' env-status.json

# Example output:
{
  "timestamp": "2026-01-14T15:30:22+00:00",
  "project": "wispy-poetry-52762475",
  "local_vars": [
    {
      "name": "DATABASE_URL",
      "environments": {
        "production": true,
        "preview": true,
        "development": true
      }
    },
    {
      "name": "BETTER_AUTH_SECRET",
      "environments": {
        "production": false,
        "preview": false,
        "development": false
      }
    }
  ]
}

🐛 Troubleshooting

Error: "Not authenticated"

Cause: Vercel CLI not logged in.

Solution:

bash

vercel login

# Or use token
export VERCEL_TOKEN="your-token"
vercel whoami

Error: "No project linked"

Cause: Local project not connected to Vercel.

Solution:

bash

vercel link --yes

# Verify
cat .vercel/project.json

Error: Variable Not Updating

Cause: Using old rm + add pattern fails sometimes.

Solution: Scripts now use vercel env update:

bash

# Old (deprecated)
vercel env rm VAR production --yes
echo "value" | vercel env add VAR production

# New (recommended) - used in env-push.sh
printf "%s\n" "value" | vercel env update VAR production --yes

Warning: "Validation failed"

Cause: Variable value doesn't meet validation rules.

Example:

bash

❌ BETTER_AUTH_SECRET debe tener al menos 32 caracteres

Solution: Generate valid secret:

bash

# Generate 32+ character secret
openssl rand -base64 32

# Update .env.local
echo "BETTER_AUTH_SECRET=$(openssl rand -base64 32)" >> .env.local

# Push again
./scripts/env-push.sh --env production

Error: "Permission denied" on scripts

Cause: Scripts don't have execute permissions.

Solution:

bash

chmod +x .github/skills/vercel-env-sync/scripts/*.sh
chmod +x .github/skills/vercel-env-sync/lib/*.sh

Issue: Git Bash on Windows

Symptoms: Array errors, variable parsing issues.

Cause: Git Bash has limited bash 3.x compatibility.

Solution: Scripts are tested and compatible with Git Bash. If issues persist:

bash

# Use WSL instead
wsl bash ./scripts/env-audit.sh

# Or use PowerShell equivalent (create wrapper)

📚 Best Practices

1. Never Commit .env Files

gitignore

# .gitignore
.env
.env.local
.env.*.local
.env.backup.*

2. Keep .env.example Updated

bash

# After adding new variable
echo "NEW_VAR=example-value" >> .env.example

# Commit .env.example (without real values)
git add .env.example
git commit -m "Add NEW_VAR to env config"

3. Use Secure Secrets

bash

# Good: Random 32+ characters
openssl rand -base64 32

# Good: Random hex
openssl rand -hex 32

# Bad: Weak password
changeme123

4. Separate Environments

bash

# Development: localhost
NEXT_PUBLIC_APP_URL=http://localhost:3000

# Production: real domain
NEXT_PUBLIC_APP_URL=https://thesimpson.webcode.es

5. Validate Before Deploy

bash

# Pre-deploy checklist
./scripts/env-audit.sh && vercel --prod

6. Use vercel env run for Dev

bash

# Instead of maintaining .env.local
vercel env run -- pnpm dev

# Always uses latest Vercel values

7. Backup Before Mass Changes

bash

# Auto-backup (default in env-push.sh)
./scripts/env-push.sh --all-envs

# Manual backup
source lib/env-functions.sh
vercel::env::backup production
vercel::env::backup preview
vercel::env::backup development

📖 Quick Reference

Essential Commands

bash

# Health check
source lib/env-functions.sh && vercel::env::health_check

# Audit all environments
./scripts/env-audit.sh

# Push to all environments
./scripts/env-push.sh --all-envs

# Pull for development
./scripts/env-pull.sh

# Dry-run sync
./scripts/env-push.sh --all-envs --dry-run

# Force update existing vars
./scripts/env-push.sh --all-envs --force

# JSON output
./scripts/env-audit.sh --json

# Backup specific environment
source lib/env-functions.sh && vercel::env::backup production

Vercel CLI Commands (Modern)

bash

# List variables
vercel env ls
vercel env ls production
vercel env ls preview --json

# Create variable
echo "value" | vercel env add VAR_NAME production
echo "value" | vercel env add VAR_NAME production --sensitive

# Update variable (Vercel CLI 33+)
echo "new-value" | vercel env update VAR_NAME production --yes
printf "%s\n" "new-value" | vercel env update VAR_NAME production --sensitive --yes

# Remove variable
vercel env rm VAR_NAME production --yes

# Pull to local file
vercel env pull .env.local
vercel env pull .env.local --environment=production
vercel env pull .env.local --environment=preview --git-branch=feature-x

# Run command with env vars
vercel env run -- pnpm dev
vercel env run -e production -- pnpm build

Function Library

bash

# Source functions
source .github/skills/vercel-env-sync/lib/env-functions.sh

# Verification
vercel::check_cli                    # Verify Vercel CLI installed
vercel::authenticated                # Check if logged in
vercel::project_linked               # Check if project linked
vercel::env::health_check            # Complete health check

# Environment variable operations
vercel::env::get_local_value VAR     # Read from .env.local/.env
vercel::env::get_local_vars          # List all vars in .env.example
vercel::env::exists VAR production   # Check if var exists in Vercel
vercel::env::is_sensitive VAR        # Check if var is sensitive
vercel::env::validate_value VAR val  # Validate value format
vercel::env::set VAR val production  # Create/update var
vercel::env::remove VAR production   # Delete var
vercel::env::pull .env.local dev     # Download vars
vercel::env::diff production         # Compare local vs Vercel
vercel::env::backup production       # Create backup

🔗 Related Skills

•vercel-cli-management - General Vercel CLI usage
•nextjs16-proxy-middleware - Middleware using env vars
•neon-database-management - DATABASE_URL management

📚 References

Last Updated: January 14, 2026
Version: 2.0 (Modern Vercel CLI)
Compatibility: Vercel CLI 33+, Bash 4+, Git Bash (Windows)

Vercel Environment Variables Sync

🎯 When to Use This Skill

📦 Skill Components

Scripts (./scripts/)

Libraries (./lib/)

🚀 Quick Start

Installation

Basic Workflow

📖 Core Patterns

Pattern 1: Audit Before Deployment

Pattern 2: Push Local Vars to Vercel (Modern Approach)

Pattern 3: Pull Variables for Development

Pattern 4: Run Commands with Vercel Env (Modern)

Pattern 5: Validate Values Before Push

Pattern 6: Sensitive Variables Auto-Detection

Pattern 7: Automated Backups

🔧 Advanced Patterns

Pattern 8: CI/CD Integration

Pattern 9: Git Branch-Specific Variables

Pattern 10: JSON Output for Programmatic Use

🐛 Troubleshooting

Error: "Not authenticated"

Error: "No project linked"

Error: Variable Not Updating

Warning: "Validation failed"

Error: "Permission denied" on scripts

Issue: Git Bash on Windows

📚 Best Practices

1. Never Commit .env Files

2. Keep .env.example Updated

3. Use Secure Secrets

4. Separate Environments

5. Validate Before Deploy

6. Use vercel env run for Dev

7. Backup Before Mass Changes

📖 Quick Reference

Essential Commands

Vercel CLI Commands (Modern)

Function Library

🔗 Related Skills

📚 References

Scripts (`./scripts/`)

Libraries (`./lib/`)