Grammarly is the most mature AI writing tool on the market. Its browser extension works everywhere — email, docs, social media — catching errors you'd otherwise miss. The free tier handles basic grammar well, while Premium ($12/mo) adds tone detection and AI rewriting that genuinely improves business communication. For teams, the Business plan adds style guides and analytics. The main limitation is that it's focused on editing, not generating content from scratch.
Grammarly is the leading AI writing assistant that checks grammar, spelling, punctuation, and style. The premium tier adds tone detection, plagiarism checking, and AI-powered rewriting suggestions.