Self-hosted LanguageTool server[0] with browser addon. 18 gigabytes of n-gram data plus machine learning models. You can catch tpyos on 64K of RAM, but not any deep grammar mistakes, un-idiomatic phrases, or mistakes in common proper names.

[0] https://dev.languagetool.org/http-server.html

Sounds like a lot of heavy lifting for something that is maybe slightly better than spell checking 25 years ago.

consider harper instead. I'm using it right now and it highlighted first two words of this comment. https://writewithharper.com/

/o\ all this just for what exactly?

To make fewer grammar mistakes.

At one point that was less than $100 of RAM which isn't a big deal for the trade.

Oh, the 18 gigabytes is not RAM, it's the storage. Language Tools indexes into the n-grams, so it doesn't have to keep everything in memory.

If you're asking a self-hoster "why" then you are asking the wrong question

well, yes. sorry.

I should have asked what is it there in replacing yourself with a mishmash of external world.

there's much more to writing voice than sticking with terrible usage.

Grammatik ran in 64K of RAM on a Z80 running CP/M. (The binary included a Forth interpreter so there was a lot of straight up code compaction.) So yeah, you could catch a lot of common English-language infelicities in a startlingly resource constrained environment... in 1983. Certainly a lot more than typos.

(The reason I remember this bright and shiny data point is I spent a week or three reverse engineering it and getting access to the inner interpreter; the office staff actually used it, though.)