Grammarly is a extremely useful browser extension but it not being free and open source makes me want something better. Alternativeto.net had a few recommendations but nothing that seemed great. Any recommendations or git hub projects I can help with?
Grammarly and anything like it is literally just a linter for prose. A couple of years ago I set up Atom text editor with a few different libraries and packages, some of them cloned from Grammarly, to lint my writing.
You can configure it with any styleguide you need i.e. journalistic, professional, informal, etc etc. Do a little digging, it’s all out there and lots of it is FOSS.