Grammarly

Grammarly is the most widely deployed writing assistant in the world, available as a browser extension, desktop app, and native integration inside Microsoft Word and Google Docs. The free tier handles spelling and basic grammar errors reliably. Premium at $12/month on an annual plan adds tone detection, sentence-level clarity rewrites, a plagiarism checker, and full-sentence suggestions — the features most users actually need. Business at $15/user/month layers on a shared style guide so entire teams write with consistent voice.

GrammarlyGO is the AI drafting layer: it can generate first drafts, rewrite existing text, and adjust tone on command within any document you are already editing. The tool works across virtually every web interface without requiring copy-pasting anywhere. Its analysis is fast, unobtrusive, and accurate on surface-level issues, though it consistently misses the kind of structural or argumentative problems a human editor would catch.