I want to test some URLs in a web application I'm working on. For that I would like to manually create HTTP POST requests (meaning I can add whatever parameters I like).
Is there any functionality in Chrome and/or Firefox that I'm missing?
I have been making a Chrome app called Postman for this type of stuff. All the other extensions seemed a bit dated so made my own. It also has a bunch of other features which have been helpful for documenting our own API here.
Postman now also has native apps (i.e. standalone) for Windows, Mac and Linux! It is more preferable now to use native apps, read more here.