[Croak]

I write most of my stuff in vim so use a neither a spellchecker or grammar-checker. I have found that since I started doing that my spelling has greatly improved. My grammar can be janky sometimes, but I have doubt programs will help with that. If I want to be sure of my spelling I might find some textbox on some website and paste the text there.

[cpach]

If you happen to use Vim, I think it has a built-in spellchecker.

[Croak]

That's correct, but I haven't set it up for my native language.