Grammarly is an AI-powered writing assistant providing real-time grammar, spelling, punctuation, and style suggestions. Available as a browser extension, desktop app, and mobile keyboard, it works across virtually every writing platform. The platform uses advanced NLP and machine learning to understand context, tone, and intent going far beyond simple spell-check. In 2026, features include generative AI writing, tone detection, inclusive language suggestions, and plagiarism checking. The free tier covers basic grammar and spelling. Premium at 12 dollars monthly includes full AI features and plagiarism detection. Grammarly delivers 95% grammar error detection accuracy with context-aware suggestions for multilingual support across 27 plus languages. Best for business communication, academic writing, content creation, and non-native speakers.