Does anyone have any recommendations for applications or browser plugins that make browsing and visualizing JSON APIs easy. Please support your answer with a reference or link to the application you recommend.
This one looks quite good, it's a firefox plugin called JSONView
https://addons.mozilla.org/en-US/firefox/addon/10869
Also ported to a chrome extension
https://chrome.google.com/webstore/detail/chklaanhfefbnpoihckbnefhakgolnmc
Addition
Postman is an awesome stand-alone program for working with APIs
https://www.getpostman.com/