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Harper vs Outwrite: catalog facts
Harper	Outwrite
Free Free and open source.	Freemium Free grammar checking, with style features in a premium plan and a Teams plan.
macOS, Web, Browser extension, Command line	Web, Browser extension
All checks run locally with no telemetry Works in browsers, editors and system-wide on macOS	Works in Google Docs, Gmail, Word and Outlook Paraphrasing and passive voice fixes
English only Rule-based checks do not rewrite text the way AI assistants do	Style suggestions require the premium plan Supports only English, French and Spanish
Downloadable app, Web application, Browser extension	Web application, Browser extension
Open source	Closed source
License not stated	License not stated
Not stated if an account is needed	Account needed
Works offline	Not stated if it works offline
Official website Full listing and sources Checked September 26, 2026	Official website Full listing and sources Checked September 26, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.