This is a very useful add-on to Firefox. It's much more than a spelling checker, having a very good grasp of grammar and a reasonable ability to determine which word you meant to type. It's not perfect, but it's an excellent tool, as long as you don't follow it blindly.

El millor corrector de català del món.

Seems to do its job and stay out of the way... key for any grammar and spelling checker. Funnily enough it doesn't work in this box 🤣

Recommended those who don't know how to spell!