A good extension is User-Agent Switcher. This extension allows you to change your real device identity to a virtual one. For example, if you can’t access a website from your mobile device because it requires a computer, you can open User-Agent Switcher and select a desktop device type and operating system — and vice versa.

Youtube videos pause and buffer infinitely at exactly 1 minute with this addon enabled, used to not do that

I was whining to Gemini about Google Maps and YouTube being horrendously slow compared to Chromium browsers. It recommended a User Switcher app. I installed this one and HOLY CRAP ! Google Maps in streetview moves at Chrome speed !

doesnt work

This extension does way more harm than good.

While it does seem to do what it claims to be doing, in practice using this is shooting yourself in the foot.

This is because it appears that with this extension active and set to pretend to be a different browser, websites perceive you as a bot.

On a vast amount of websites you will run into an impassable cloudflare captcha verification screen. You try to solve it - it fails and loops back around. It will keep failing until you deactivate this extension.

On youtube, any comments you leave will be automatically shadowbanned. Presumably because it detects you as a spam bot.

So I honestly don't see much point in using this.

On the surface, a simple extension. Underneath, a powerful extension that enables you to view websites often in ways that run faster and disable pushing their APP to your phone. I consider it more advanced power user stuff, so I do wish there was a way to simplify things visually for more people to enjoy the advantages here. Maybe even a built-in database of known good user agents per website.

Doesn't work

Easy to use (although a bit confusing if you're using it for the first time) and does as advertised.

The only issue I've seen recently is that videos on YouTube stop playing after a few seconds and an unexplained error prevents the video from playing every single time. Disabling this add-on instantly resolved this issue. I will change the rating to a 5-star as soon as I find a way for the addon to work again without this disturbance, or this issue is patched.

I have changed to a different agent switcher as this one causes a Cloudfare verifying continuous loop.

I use this extension for many years now. But sadly the development is very slow. It's very outdated, you're stuck with very old and on many websites not anymore supported browser-versions to choose from like Firefox 134, Firefox 128 ESR, Safari 17, Edge 131. Also no matter which browser you choose from, on browserleaks.com/javascript its still possible to see that mozilla is used (the parameter appCodeName shows "Mozilla". So please ntninja update the extension!

Edit (2025.11.05):
In it's actual deprecated state this browser extension breaks the Cloudflare Bot Challenges.
If a website uses any of Cloudflares Anti-Bot Challenges it will break the website and render it useless.

Please add a redefinition for Yandex Browser (Window), because I'm tired of seeing annoying ads in Firefox every time I search!
PS: Windows / Yandex 25 [Desktop]: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:135.0) Gecko/20100101 Firefox/135.0 - didn't work

i use this to switch to linux to get windows iso

小心使用此插件，该插件可能会导致Cloudflare反复验证

非常感谢，它自由度高。