AWS CloudFront Function Tester

About This Tool

The CloudFront Function Tester provides an environment for writing and testing CloudFront Functions code directly in your browser. CloudFront Functions run at the edge for viewer-facing request and response manipulation, and testing them locally before deployment prevents edge errors that are difficult to debug. This tool lets you write function code, define test events with custom headers, query strings, and URIs, and see the output immediately.

When to Use This Tool

• •Test URL rewrite functions that redirect requests, add trailing slashes, or map clean URLs to backend paths.
• •Validate header manipulation functions that add security headers, modify cache keys, or set CORS headers on responses.
• •Debug query string normalization functions that sort, filter, or transform query parameters for cache optimization.
• •Test A/B testing functions that route viewers to different origins based on cookies or headers.

Frequently Asked Questions

What is the difference between CloudFront Functions and Lambda@Edge?

CloudFront Functions run at all 400+ edge locations, execute in under 1 millisecond, and support only viewer request/response events with a JavaScript runtime. Lambda@Edge runs at regional edge caches, supports all four event types including origin events, allows Node.js or Python, and has higher memory and execution time limits.

Does this tool deploy functions to CloudFront?

No. This tool provides a browser-based testing environment. Once your function works correctly, you deploy it through the CloudFront console, CLI, or infrastructure-as-code tools.