AWS CDK Diff GitHub Action

Post formatted CDK diff output as comments on Pull Requests. Review infrastructure changes before deploying.


Stop checking pipeline logs just to see what infrastructure changed. The AWS CDK Diff GitHub Action posts formatted CDK diff output directly to your Pull Request, so you can review changes where you're already doing code review.

Why Use This

❌ Without CDK Diff Action

✅ With CDK Diff Action

  • Automatic PR comments - Formatted CDK diff appears directly in your Pull Request
  • Smart updates - Refreshes existing comments instead of creating duplicates
  • Clear formatting - Highlights IAM changes, Security Groups, Parameters, and Resources separately
  • Fast execution - Built with native JavaScript, no Docker container startup overhead
  • Clean PRs - Skips posting when there are no changes

What Gets Posted

The action parses your CDK diff and organizes it into readable sections:

  • IAM Statement Changes - Policy modifications that affect permissions
  • Security Group Rules - Network access changes
  • Parameter Changes - CloudFormation parameter updates
  • Resource Changes - Additions, updates, and deletions

Each section is collapsible, so reviewers can focus on what matters most.

Who Is This For

Development teams using AWS CDK who want to:

  • Review infrastructure changes without leaving GitHub
  • Catch potential issues before deploying
  • Speed up PR reviews with clear infrastructure visibility
  • Keep a record of what changed in each PR
What You WantWhere to Go
Get startedInstall Guide
See examplesUsage Examples
Configure inputsConfiguration Reference

Ready to Start?

Head to the Install guide to add the action to your workflow. If you want to see how it works first, check out the AWS CDK Starter Kit - it has this workflow already configured.

Resources