For a URL alias, you can create one or more port mappings which associates a port with a resource. Port mappings allow the use of a single URL alias with multiple resource paths, because each port can be mapped to a different URL path.

When API Gateway receives a request that contains a URL alias, API Gateway resolves the request destination by first determining if there is a URL path associated with the incoming port. If there is no URL path mapped to the port number, then API Gateway uses the default URL path for the alias as the request destination. The port mappings are always evaluated first.