It really works! I loved it..

9/10

...

Very useful add on!! 100% recomended

Useless for developers. There's very few predefined user agents and there's no easy way to add your own

You'd think there's be an option to fake your Firefox version, too. I remember there being an extension that let me do this and thought this was it. Too bad.

Android Firefox not work...

Android版Firefoxでうまく動きません…

Muy Buena

This user agent switcher works well with Firefox Quantum, it modifies the user agent via the HTTP request header and also the JavaScript property navigator.userAgent.
I noticed it does not take effect on https://addons.mozilla.org, I don't know if it is a feature or a bug.

Recommendation: instead of displaying deprecated mobile operating systems like Symbian and Firefox OS, the addon should add Sailfish OS to the list (maybe BlackBerry also).

It would be good to add the possibility to enter multiple custom user agent instead of just one, like this addon (not supported with latest Firefox): https://addons.mozilla.org/en-US/firefox/addon/user-agent-switcher/

很好。很方便。

Wq

I installed this on FF 57 running on Fedora 25. No matter how I configured it, it showed that I was running FF 52 under Windows, even after I restarted FF. I uninstalled it, restarted FF and no change. I had to go into about:config to undo the damage. Utterly worthless.

It works and support Firefox Quantum 57.0.

I used Random Agent Spoofer which does not work in FF57. This extension is about as good. Does not randomize automatically, but easily changed with a few clicks. Just as with R. A. S., Youtube knows Google's Chrome browser and will not allow you in the site. Just spoof another browser temporarily and go on.

Worked well for a long time. Now I am getting constant reCaptcha hCaptcha and all sorts of Cloudflare flags...
It is a shame that you cannot change the user-agent on url-based or tab based.