Cloud CDN lets you add custom code to the request processing path of global external Application Load Balancers by using Service Extensions edge extensions

## Feature Cloud CDN lets you add custom code to the request processing path of global external Application Load Balancers by using Service Extensions edge extensions. These extensions help you implement customizations in the request path pre-cache, which can influence how content is cached and the backend service is selected on the Application Load Balancer. This feature is in **Preview**. For more information, see [Use Service Extensions for edge computing](https://cloud.google.com/cdn/docs/integration-with-service-extensions).