I’ve just released a free API Console tool that takes an interesting approach to debugging REST API requests. You can find it at http://140dev.com/twitter-api-console/.
It allows you to quickly run any API call with your own OAuth tokens and get back the headers and response message in a pretty-printed display. It also displays a PHP version of your request formatted for the tmhOAuth library. You can copy and paste this directly into your own code.
My favorite feature is the ability to share a complete API request as a URL, so others can run the same request with a single click. I’m hoping this will help with reporting API issues here.
Please share your comments and suggested improvements for this API Console with me. I want to build this into a useful API development tool.