Good but not working on FF developer Rated 4 out of 5 stars

Looks a pretty good add-on. However, not working on FF developer 52.0a2 (2016-12-19) (64-bit). Nonetheless could see the LT button on the upper-right bar, nothing but a blank panel appears when clicking the LT button....

doesn't seems to work on mobile Rated 3 out of 5 stars

I tried it on Firefox Mobile on android. I didn't manage to make it work.

It's indeed not supported on mobile. But I wonder how you even managed to install it? On https://addons.mozilla.org it shouldn't even be offered when on a mobile device.

Locally hosted instance of languagetool Rated 5 out of 5 stars

Great! If you don't like sending your data to a third party network you can use this add on with a locally hosted instance on your computer or on a private network.

I simply run language tool from the command line like this:

languagetool --http --allow-origin "*"
default port is 8081 but you can specify another one by adding this : --port 666

then in the add on preferences simply change the LanguageTool API Server URL to:
http://localhost:8081/v2/

Very useful tool Rated 5 out of 5 stars

LanguageTool is a very useful spell- and grammar checker. It is easy to use and open source. A must have if you want to write in a language that is not 100% in your grasp.

This review is for a previous version of the add-on (1.0.1). 

Rated 5 out of 5 stars

The new version significantly improved the usability of this very useful add-on! Keep up the good work!

This review is for a previous version of the add-on (1.0.1). 

LanguageTool для FireFox48+ Rated 5 out of 5 stars

Великолепно!
По сравнению с LanguageToolFX, появился пользовательский словарь, быстрая возможность выбора языка в окне проверки!

This review is for a previous version of the add-on (1.0.0).