The private, on-device writing assistant for Mac. Fix grammar, sharpen tone, and rewrite anything — in every app — for one payment, forever.
Grammarly costs around $144 every year, reads everything you type, and sends it to their servers. GrammarGem does the same job — better — entirely on your Mac, for a single payment.
Select text in any app, press one hotkey, and it’s polished in place. No copy-paste, no switching windows, and nothing ever leaves your machine.
“One payment and it’s mine forever — such a bargain.” 👍
| Grammarly | GrammarGem | |
|---|---|---|
| Price | ~$144 / year, forever | Pay once |
| Your words | Sent to the cloud | Never leave your Mac |
| Works offline | ❌ | ✅ |
| Where it works | Where the extension reaches | Every app, system-wide |
| Speed | Round-trip to a server | Instant, on-device |
- ⚡ Instant corrections — grammar, spelling, punctuation, and clarity, fixed the moment you ask.
- 🔒 Private by design — everything runs on your Mac’s Neural Engine. Your writing is never uploaded, logged, or used to train a model.
- ⌨️ One global hotkey — fix or rewrite the selected text in any app: Mail, Slack, Notion, Chrome, Messages, VS Code, and more.
- ✨ Ask & rewrite — “make it shorter,” “more formal,” “translate to German” — done in place.
- 🎚️ Writing Modes — Email, Post, Team Chat, Academic, Code — switch the tone instantly, or let GrammarGem pick the right one for the app you’re in.
- 📖 Personal dictionary — teach it your names, brand terms, and jargon once; it stops “correcting” them forever.
- 🖥️ A clean management app — manage your devices, shortcuts, modes, and privacy from one tidy window.
No subscription. No per-seat fees. One payment, lifetime updates.
| Plan | Price | Devices |
|---|---|---|
| Solo | $39 | 1 Mac |
| Personal ⭐ | $59 | 2 Macs |
| Studio | $89 | 4 Macs |
| Startup License | $159 | 10 Macs |
Apple Silicon · macOS 14+ · 14-day money-back guarantee, no questions asked.
Is my writing really private? Yes. Every correction and rewrite runs on your Mac. Your text is never uploaded, logged, or used for training.
Do I need internet? No. Core features work fully offline.
Is this a subscription? No — it’s a one-time purchase with lifetime updates and a 14-day money-back guarantee.
What about plagiarism detection? GrammarGem is private-first, so it doesn’t do cloud plagiarism scanning — that would require sending your writing to a server. Everything else you’d expect is here.
GrammarGem is open source under the MIT License. We believe a privacy tool should be one you can actually inspect. Issues and pull requests are welcome.
© 2026 FounderGem LLC · 1309 Coffeen Avenue STE 1200, Sheridan, WY 82801, USA