Grammarly

Grammarly catches the mistakes that get noticed in a sponsor email or a video description, and it does it inside whatever box you are typing in rather than in a separate app. The free tier covers spelling, grammar and tone. Rewriting, plagiarism detection and the larger prompt allowance sit behind Pro.

Free covers spelling, grammar, tone and 100 AI prompts a month. Pro is $12 a month with 2,000 prompts, rewrites, plagiarism detection and unlimited suggestions, and starts with a 7-day trial that takes no payment up front and emails a reminder two days before it ends. Enterprise is quoted and is sold through Superhuman Go.

Anybody writing descriptions, emails and scripts in public, whose mistakes get screenshotted. A writer who wants help with structure and argument rather than correctness will find it shallow.