- Grammarly
- It has a macOS app that hooks into every desktop app through accessibility APIs
- Premium: $12/month (billed annually)
- 🆕 Generative AI features
- LanguageTool
- Open core
- Premium: €3.99/month (billed annually)
- Can be self-hosted for maximum privacy
- Self-hosted version is the free SaaS version, no way to self-host the premium language rules
- ”For larger business customers, we also offer an on-premise premium version.”
- HTTP API → Obsidian integration: https://github.com/Clemens-E/obsidian-languagetool-plugin
- Has been around for 10 years based on GitHub history
- Supports 30+ languages
- Free vs. premium
- Pricing page gives actual examples of the rules that are premium only
- Looks like there are many premium rules that Grammarly offers for free
- ProWritingAid
- Browser extension only
- The desktop app is only available in premium
- Premium: $10/month (billed annually)
- Harper
- ”Harper tries to do one thing well: find grammatical and spelling errors in English text.”
- Written in Rust
- 100% local and private
- List of rules
- Missing features as of 2025-01-15:
As of 2023-02-03:
- Both Grammarly and LanguageTool can be used outside of browsers on the desktop
- As a free user, Grammarly checks more error types
- As a paid user, features are more or less the same, but Grammarly is 4x more expensive than LanguageTool