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