Grammarly is an AI-powered writing assistant built by Grammarly, Inc. that checks grammar, spelling, and tone and rewrites text across apps and websites. It runs on a freemium model with a genuine free tier, and the paid Pro plan averages $12 per month ($144 billed per year), with an Enterprise tier above it for teams that need shared administration and APIs.
Who builds it
Grammarly is developed by Grammarly, Inc. The company builds both the consumer-facing browser extension and desktop apps and a developer-facing API, so the same underlying grammar, spelling, and tone technology reaches users directly and through third-party integrations.
What it does
Grammarly checks and corrects grammar and spelling, analyzes the tone of a piece of writing by examining word choice, phrasing, punctuation, and even capitalization, and can rewrite text to adjust that tone. The tone checker in particular is presented as a way to catch writing that might land as too blunt, too casual, or unintentionally negative before you hit send. Because Grammarly works as an extension and app layer rather than a standalone editor, it operates across the apps and websites you already write in — email, docs, social media, and more — rather than requiring you to copy text into a separate tool.
Core features
- Freemium pricing with a genuine free tier and Pro averaging around $12/month ($144/year)
- Tone detection that analyzes word choice, phrasing, punctuation, and capitalization
- Tone-adjustment and rewriting on top of grammar and spelling corrections
- Works across apps and websites rather than a single dedicated editor
- Grammarly for Business plans with billing groups and single subscriptions for whole teams
- A REST API that brings Grammarly's grammar, spelling, and tone technology into an organization's own applications and platforms
Who it's for
Grammarly suits anyone who writes across many different apps and websites and wants consistent grammar, spelling, and tone checking without switching tools — students, professionals, and non-native English writers alike. Because it operates as a layer on top of the writing surfaces you already use, it fits naturally into workflows where switching to a dedicated writing app isn't practical. The free tier covers core grammar and spelling checking; Pro adds deeper tone adjustment and rewriting for around $12/month. Organizations that want Grammarly rolled out across a whole workforce, with centralized billing and admin controls, use Grammarly for Business, and developers who want Grammarly's AI checking built into their own product use the Grammarly API.
Data and compliance
Grammarly states that its SOC 2 (Type 2) report validates its controls against the security, privacy, availability, and confidentiality trust services criteria. We don't track a specific statement in our data on EU-only data hosting or on whether free-tier text is used to train Grammarly's models — organizations with strict data-residency or training-opt-out requirements should confirm current terms directly on Grammarly's own security and privacy pages before rolling it out at scale.