I like that it still allows custom sources.

Really nice, and for me at least, it even seems to be free!

Had to open an account just to write that that add-on basically is dead recently. Can't even show basic mistakes and shows mistakes when there aren't any. That add-on is barely working these days.

Also note that Mozilla has removed their "recommended badge" recently for that extension...

I’ve been using LanguageTool for over 2 years and I really liked it — until about a month ago.

Recently, the extension started causing extreme RAM usage while typing. I have 32 GB of RAM, and during normal use I sit at around 18–20 GB. However, as soon as I start typing in a text field where LanguageTool is active, memory usage quickly spikes to 30–32 GB within seconds, which often leads to Firefox freezing or crashing completely.

This happens multiple times a day. In some cases, just 10–15 seconds of typing is enough to crash the browser. I even had to start writing messages in external apps (like Notepad) and then pasting them, just to avoid crashes — which completely defeats the purpose of using this extension.

What’s strange is that:
- this problem only started about a month ago,
- before that, I had zero crashes for over 2 years,
- I didn’t notice any recent updates that could explain this behaviour.

At this point, the extension has become unusable for me due to its massive resource consumption.

That said, aside from this issue, I really liked LanguageTool and I hope this gets fixed soon.

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.

Très utile.

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 🤣

Used to be pretty good. But for the last 2 weeks, it has been eating ram until the browser crashes