Use this add-on if you care about your privacy.

I have used before and I will know soon how it is with firefox ?

This addon uses tracking cookies per uBlock Origin and other cookie blocking addons. Otherwise, the plugin seems excellent.

Wow, how is this free? I expect more improvements in the future keep up the good work!

Hermosa

Absolutely love this. Unlike Grammerly I can use it on your tube and EBay my only problem is where is the "British English" option? Sorted Thank you! One happy bunny now.

Excelente herramienta

This addon is good but has some disadvantages burdens the operation of the browser and so websites, :-( while I would like such problems with this extension was not and I hope that over time it will change for the better by making another very large update : - )

The best grammar checker around!

Les meilleurs !!! J'ai tout de suite été conquis : c'est le coup de foudre. J'ai même acheté la version Plus !
Je viens de renouveler mon abonnement pour une deuxième année ;-)

It is barely more useful than the default spell checker. What I wanted from this is an auto-detect for auto-switching languages. It hasn't implemented it. It also doesn't show the squiggly lines and is quite buggy.

But above all, it uploads every keystroke to its corporate servers... So... uninstall immediately, how bloated and intrusive is that? No thank you, either take all the code to the client add-on or don't make a spelling add-on at all....