excellent !

Od kilku lat niezbędne dla mnie narzędzie. Sprawdzam nim treści i tworzone przez siebie UI.

hervorragendes Tool,
das ich gut zum Schreiben meiner Bücher gebrauchen kann

The spell check system automatically checks punctuation first and highlights text in yellow ...which automatically blocks/disables spell check itself, how come there is no way to configure the order of these options

This is not a local spellchecker (all browsers use to have local spellcheckers)
"LanguageTool" forwards all of your text to third party servers (wasting data and adding latency) and does not show you errors until responses are received from those servers (huge lag)
Mobile Firefox removed its spellchecker because Android had a spellchecker, but Google removed Android's spellchecker because most browsers has spellcheckers.
LanguageTool is now the sole result for https://addons.mozilla.org/en-US/android/search/?q=spell%20checker but our business does not allow apps that forward text to remote servers.
Now 4 stars due to responses about local servers

I'm so sad this add-on isn't working anymore. I've used this for over a year and it was incredible, even without accessing the paid tools. Today I starting working as usual, correcting some papers, and I saw the tool didn't catch very simple mistakes (one of the sentences was "I cook burger and pizza"). IDK what happened, but I'll be deleting the extention for now.