English: Grammarly

Grammarly is trusted by students, professional writers, business people, bloggers, and people who just want to write better. No matter what your writing situation is, Grammarly adapts to your needs, giving you the confidence of mistake-free writing every time you write.

Grammarly is apparently free! But only on Chrome, Safari, and Firefox browsers.

A Better Way to Write
Grammarly makes you a better writer by finding and correcting
up to 10× more mistakes than your word processor.
Instantly find and correct over 250 types of grammatical mistakes.
Detect plagiarism by checking your text against over 8 billion web pages.

Grammarly is the world’s most accurate grammar checker

250 points of grammar
Grammarly scans your text for proper use of more than 250 advanced grammar rules, spanning everything from subject-verb agreement to article use to modifier placement.

Contextual spelling checker
Correctly spelled words used in the wrong context mean embarrassing mistakes for you. Grammarly spots erroneous use of lose/loose, affect/effect, lie/lay, there/their/they’re, and many other commonly confused words.

Vocabulary enhancement
Words can make an impact, or they can fall flat. Enhance your sentences with Grammarly’s context-optimized word choice suggestions to instantly improve the readability of your document.

https://www.grammarly.com/1