You're right! recroom works well with WebIDE. You build your app and can then use WebIDE (and even the Ember Inspector Firefox add-on) to debug your app, for instance in the Firefox OS Simulator.

Future plans of ours include having recroom (and really, any toolchain; this is not a privilege we only want Mozilla projects to have) integrate even more smoothly with the WebIDE, with more direct integration points like "pre-push hooks".

I just found out yesterday Chrome has one as well https://chrome.google.com/webstore/detail/chrome-dev-editor-...