Grammarly - Clear, effective, mistake-free writing everywhere you type.

Expresso - The award-winning Expresso editor is equally suitable as a teaching tool for the beginning user of regular expressions or as a full-featured development environment for the experienced programmer with an extensive knowledge of regular expressions.

Kodezi - Grammarly For Programmers

Hemingway - Hemingway App makes your writing bold and clear.

Synonymful - Improve your vocabulary and communicate like a pro.

Grammar Snob - Markup your friends' iMessages like an English teacher 😁