Is there a service that, in response to an http request, sends the headers of this request, along with the ip-address from which the request was sent?

Question

Computer networks

I'm making http requests through proxies and want to make sure these proxies don't mangle my request headers. Those. I want to see how my request looks on the target server and what ip it comes from.
Surely there is some service for this, but Google did not help me.