Grammarly

Grammarly began as a grammar checker and has grown into a full AI writing assistant that works across your browser, desktop apps, email, and documents. It catches errors, tightens phrasing, and adjusts tone in real time.

Its generative features draft replies, rewrite paragraphs, and summarize threads, while the classic suggestions remain the most trusted proofreading layer in the industry. Style guides and snippets keep teams consistent.

The free tier handles correctness basics; Pro adds rewrites, tone control, and plagiarism checks. Because it follows you across every app, Grammarly is the lowest-effort writing upgrade available.