Comment by hombre_fatal

Unfortunately, Language Tool seems limited to very basic mistakes.

It's Spanish demo only highlights some mechanical punctuation, gender, and plurality errors though it has one useful suggestion for a word that is too specialized.

Useful, for sure, but Grammarly is much more helpful, pointing out things like run-on sentences, clauses that lack parallel verbs, and things like that. Maybe it's better in English, but hopefully Language Tool can get to that level one day.