Grammarly: The Writing Assistant Everyone's Used Without Realizing

Grammarly is the browser extension and app that underlines your typos in red and your 'bad' sentences in blue. It started in 2009 as a grammar checker for students, and by 2026 it is a full AI writing assistant that can rewrite, summarize, reply to emails, and generate drafts. It is on over 500 million devices worldwide, including probably yours and most of your coworkers'.

• Catching typos, homophones ('their' vs 'there'), and punctuation errors with near-perfect reliability.
• Keeping you consistent with tone across a long email — it flags when paragraph four suddenly sounds angry.
• Working everywhere you type: Gmail, Slack, Google Docs, Notion, LinkedIn, Word, even text boxes on random websites.
• Its 'generative' feature (formerly GrammarlyGO) writes short drafts and replies in your style without you leaving the tab.
• Team-wide style guides — if your company bans 'leverage' and wants 'use', Business plan enforces it across every employee's writing.

• Long-form creative writing — it will fight your voice and try to smooth every sentence into corporate mush.
• Technical jargon — it flags valid domain terms as errors unless you add them one-by-one.
• Nuance and style — it does not understand when a fragment. Is on purpose.
• Its AI rewrites are noticeably weaker than ChatGPT or Claude. It is tuned for safety, not quality.
• Privacy — everything you type flows through their servers. Some companies ban it for legal docs.

• Free: Basic spelling, grammar, and punctuation. Limited AI prompts per month (~100).
• Premium: $12/month billed annually ($30 monthly) — full tone detection, rewrites, plagiarism check, 1,000 AI prompts.
• Business: $15/user/month — shared style guide, brand voice, admin controls, 2,000 prompts.
• Enterprise: Custom pricing, SSO, data retention controls, SOC 2 Type II.

Who should bother: anyone who writes a lot in browsers — students, professionals, ESL writers. The free tier is legitimately useful. Who shouldn't: fiction writers (it will ruin your voice), privacy-sensitive industries, anyone already paying for Claude or ChatGPT who is willing to paste text for review. In 2026, Grammarly's moat is its browser integration, not its AI.