for whom the postman rings twice

For faking AJAX GET and POST requests etc, Postman is hard to beat. It can do all kinds of thing with request headers and json payloads and what not. I didn't mess with the Chrome app but the free OSX version is pretty keen. I like the logo -- it reminds me of my own comic Young Astronauts in Love -- though it's a little odd they went with a space postman theme.