Langtool[1] is Open Source and can be either used with a subscription or selfhosted. Works well when used in combination with a few gb of n-grams [2]. There is

Langtool[1] is Open Source and can be either used with a subscription or selfhosted. Works well when used in combination with a few gb of n-grams [2]. There is also a Libreoffice plugin and most important also one for emacs. [1] https://languagetool.org/ https://languagetool.org/ [2] https://languagetool.org/download/ngram-data/ https://languagetool.org/download/ngram-data/