This works just fine on non-mobile devices. I have not tested it on mobile yet, but my review is based on my desktop/laptop experience. I have seen questions like "Why does this add-on need the user's username and password?" when pointing to the permissions requested, that ask for all browser and input data. The way this add-on works is it creates a brand new request on your behalf using the data you input, as well as the data on the website. Don't be alarmed about it, it is not storing your data. Some people who write reviews don't know how things work, don't know why certain permissions are requested, and make bad assumptions. Enjoy the app on, at least, non-mobile platforms! :)

Seems like it might work, have not had a real chance to test it. But to the developer, can you make the Option button much smaller (say about 1/4 the size) as it takes up a lot of room on the toolbar. Or make the options when we want to use it available on the Tools dropdown ? ? ? Easier to get to when we need it ... Thanks

Feature "Edit Curretn User-Agent String or Copy it to Clipboard" don't work on Firefox 52.9 ESR.

funktioniert nicht und außerdem kann man nirgends hier die deutsche Sprache auswählen.

Very useful add-on, worked well

At least for what I needed, it worked great! .... Using here over WATERFOX 56.2.7.1 (64-bit) OSx

It'll be better if it support to select a version of Windows when IE's UA is selected, but it doesn't matter that the extension can custom UA string, so I can paste UA string of IE of any version's Windows

Best add-on for Firefox. MOZILLA, HEAR ME OUT ON THIS PLEASE: "If you want to compete against all of the websites and services that may in the future, due to the superpower and monopoly known as google, deny Firefox access to certain web pages and services, automatically integrate this into the browser's main code so that whenever a site states: 'Browser not supported', it will always bypass these issues and switch the user-agent to the browser that the site says it supports. Building transforming code from chromium to gecko quantum will preserve Firefox's unique, powerful, better web rendering engine. That is the future for Firefox, and going to college next year, I will learn much about programming, security and computers, preparing me to advance Mozilla as a strong non-profit organization."