I needed to test a web page on a local web dev environment, and of course CORS isn't allowed in firefox, so this extension solved it. many thanks to the creator. much obliged.

does not work on mac osx with firefox 59.0.2 (64-bit)

It doesn't seem to work on Firefox 59.... I opened an issue on Github:

https://github.com/spenibus/cors-everywhere-firefox-addon/issues/18

Does what it says and is a great help developing / working with CORS sensible APIs.

very good !

Ich hatte es schon vor einiger Zeit getestet und es hatte nicht funktioniert. Jetzt hat es doch funktioniert und Firefox hat eine Anfrage an eine fremde Seite nicht blockiert. Ich hatte mich schon über die Bevormundung von Firefox geärgert.

working great thanks

This addon solves the CORS problem...well, so far;
Compare to Chrome, this is the first time I make CORS work with the first try!
Thanks a lot!

Solve CORS problems on my firefox browser.

Good us.

It doesn't seem to work for me.