You face the same problem if you want to just list multiple resources based on a query or a filter. The solution isn't to send a GET with an HTTP body, which is

You face the same problem if you want to just list multiple resources based on a query or a filter. The solution isn't to send a GET with an HTTP body, which is counterintuitive to most people, and many proxies just drop. It's to make your filter part of the URL (as a query parameter). Same with DELETE.