service. Grammarly ceased to be useful when it spammed up all my writing with advertisements for their premium features, which suck anyway.
LanguageToolLanguageTool is a free grammar checker and paraphraser for English, Spanish, and 30 other languages. Instantly check your text for grammar and style mistakes.
https://languagetool.org/
I used that extension and guess what? It checks my spelling and doesn't try to sell me something every time I type anything.