AWS CloudFront Functions
AWS CloudFront Functions is a serverless compute service that allows developers to run lightweight JavaScript code at the edge of the CloudFront content delivery network (CDN) to manipulate HTTP requests and responses. It enables low-latency execution for simple tasks like URL rewrites, header modifications, and request filtering directly at the edge locations. This service is designed for high-scale, performance-critical operations with minimal overhead, as functions run in a restricted JavaScript runtime.
Developers should use AWS CloudFront Functions when they need to perform lightweight, latency-sensitive transformations on HTTP traffic at the edge, such as A/B testing, request routing, or security validations, without provisioning servers. It's ideal for use cases like customizing cache keys, modifying headers for CORS, or implementing simple authentication checks, as it offers faster execution and lower cost compared to AWS Lambda@Edge for simple tasks. This is particularly valuable for optimizing web application performance and reducing origin server load in global deployments.