flymake-grammarly VS languagetool

There's also flymake-grammarly

Great tool, thanks for sharing. If you are open to suggestions, I would love to have spellcheck in it.

https://github.com/languagetool-org/languagetool

I don't know of a "global" function, but what you use depends largely on where you're doing your writing. It's possible to spellcheck markdown and html files from a terminal with aspell and to find the correct spelling of partial words with look. Some apps, like Grammarcheck can offer you close to global spellcheck. Apps like LanguageTool offer browser addons to check grammar and spelling.

Proofread for spelling, grammar, and punctuation errors (Grammarly, Hemingway Editor, LanguageTool),

Please re-read the wiki thoroughly, line-by-line, format your resume to the wiki guidelines, verify that each of your bullet points begin with a strong action verb and follow the STAR (Situation, Task, Action, and Result) or XYZ (Accomplished D as Measured by Y, by Doing Z) methods, proofread, revise, and repost your resume.

LanguageTool - I liked using Grammarly to check my writing, but it is not great for privacy considering it sends off everything you write to Grammarly servers. LanguageTool is a great open source alternative that you can run locally.

On extensions, for example, I use LanguageTool [1], which is similar to Grammarly. It could be configured with a local server, although I have a “premium” account which sends data to a 3rd party server. I trust this extension to verify my messages on HN, but I can't trust it to have access to my banking account. This is an example of a really useful extension that I'll never be able to fully trust because it has access to all websites, and it sends all that I write to another server.

In fairness, Firefox's advantage has been that Mozilla has a trustworthy manual review process for the “recommended” extensions.

[1] https://languagetool.org/