Query requests used with CloudWatch Events are HTTP or HTTPS requests that use the HTTP verb GET or POST and a Query parameter named Action or Operation. This documentation uses Action, although Operation is supported for backward compatibility.
An endpoint is a URL that serves as an entry point for a web service. You can select a regional endpoint when you make your requests to reduce latency. For information about the endpoints used with CloudWatch Events, see Regions and Endpoints in the Amazon Web Services General Reference.