I'd add that one of the best features of XHR Poster is that it uses your cookies and any authentication you've already performed in Chrome when sending the requests.

I had to build an API that lived inside a system with entirely too many authentication/cookie checks and using curl was becoming too awkward for testing, this saved me a lot of time.

Thank you so much for the pointer! I've installed it, and I imagine I'll be using it quite a bit in the coming weeks at $work.