Grammarly is the best grammar and spell checker I've used. It is great for writing just about anything you can think of. I like the suggestions it makes to help move my story on. and keep my business letters professional.

Like the app, Needs Improvement before I buy premium. Always logging in, spellchecker.net never works anymore. Works when it wants to on most pages. To buggy for now.
11-28-20

Thank you, Grammarly, for keeping the Firefox support. Please don't leave it! :)

I am honestly not impressed with this add-on at all. Everybody always talks about Grammarly and how fantastic it is, but it honestly is far from great in my opinion. It always tries to correct basic grammatical mistakes that are, in fact, not mistakes, as well as neglect to correct mistakes that are, in fact, there. I would personally prefer Linguix, which isn′t perfect either, but definitely better than this. Everything about this add-on is decent but it′s little mistakes like the ones I mentioned that it makes that prevents me from using it.

only works sometimes