When debugging an HTTP client, one of your first tests is likely to be a Google search, which lets you see whether your client does non-SSL GETs properly. Everyone knows where it is, everyone can use it, and everyone can see whether it succeeded.
My client has a problem with HTTPS POST. I can reproduce it locally with my specially set-up HTTPS server, but I want others to be able to try it as well. Is there a public web page using HTTPS where sending a test POST is not a bad idea?
Edit: In the end, the problem turned out to be that my client would cache network output by the line when sending over TLS. Obviously, that causes problems for POST but not for GET...