Preview environments have become an essential part of modern web development workflows. They allow teams to test changes in isolated, production-like environments before merging code into the main branch. In this guide, we'll explore everything you need to know to get started with preview environments.

What Are Preview Environments?

Preview environments (also known as review apps or deploy previews) are temporary, isolated instances of your application that are automatically created for each pull request or branch. They provide a live URL where stakeholders can review changes without affecting production.

Key Benefits

  • Faster Feedback Loops: Reviewers can see changes immediately without pulling code locally
  • Reduced Risk: Catch bugs and issues before they reach production
  • Better Collaboration: Designers, PMs, and clients can review work without technical setup
  • Isolated Testing: Each preview is completely separate from other environments

Setting Up Your First Preview Environment

Getting started with prev is incredibly simple. Here's how to deploy your first preview in under a minute:

Step 1: Install the CLI

curl -fsSL https://prev.sh/install.sh | sh

Step 2: Navigate to Your Project

cd your-project

Step 3: Deploy

prev

That's it! You'll receive a unique URL like https://focal-fossa.prev.sh where your preview is live.

Advanced Configuration

Custom Subdomains

Want a more memorable URL for client presentations? Use the --subdomain flag:

prev --subdomain client-demo
# Deploys to https://client-demo.prev.sh

Time-to-Live (TTL)

Control how long your preview stays active:

prev --ttl 7d  # Preview expires in 7 days
prev --ttl 24h # Preview expires in 24 hours

Environment Variables

Pass environment variables to your preview:

prev --env API_URL=https://api.staging.example.com

CI/CD Integration

The real power of preview environments comes from CI/CD integration. Here's an example GitHub Actions workflow:

name: Preview Deployment

on:
  pull_request:
    types: [opened, synchronize]

jobs:
  deploy-preview:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      
      - name: Deploy Preview
        run: |
          curl -fsSL https://prev.sh/install.sh | sh
          prev --subdomain pr-${{ github.event.number }}
        env:
          PREV_TOKEN: ${{ secrets.PREV_TOKEN }}

Best Practices

  • Use meaningful subdomain names: Include the PR number or feature name for easy identification
  • Set appropriate TTLs: Don't let previews linger indefinitely—set reasonable expiration times
  • Secure sensitive previews: Use access control for previews containing sensitive data
  • Clean up after merging: Destroy previews when PRs are merged to save resources

    • Conclusion

    Preview environments are a game-changer for development teams of all sizes. They improve code quality, speed up reviews, and make collaboration seamless. With prev, setting them up takes seconds, not hours.

    Ready to get started? Sign up for free and deploy your first preview today.