Private by design
Your life stays on your devices.
A personal agent only earns its keep if it can see your most private corners — your inbox, your calendar, your messages. So Posthorn is built to keep them private: it runs on your Mac, and your data never leaves your devices.
Why local-first isn’t optional
Most “AI for your inbox” tools work by uploading your mail to their cloud, where their servers read it. That’s a lot of trust to hand a third party — your whole professional and personal life, in someone else’s database, one breach or policy change away from exposure. Posthorn takes the opposite stance: the agent comes to your data, not the other way around.
How your data is handled
Runs on your Mac
Posthorn lives on your device. Your email, calendar, messages, and notes are read and reasoned about locally and stored in your own database — never on our servers.
You choose the AI
Bring your own Anthropic or OpenAI key and your data goes straight from your Mac to the model — we never see it. Or run a fully local model (Ollama / LM Studio) so nothing leaves your machine at all.
Encrypted sync (optional)
When iOS arrives, only your briefings sync — end-to-end encrypted on your Mac first, with a key derived from your password that we never hold. The same pattern Signal and 1Password use.
What we never do
- Sell, rent, or share your personal data
- Train AI models on your data
- Use your data for advertising
- Aggregate or analyze your data across users
- Read your encrypted synced data — we can’t, even if compelled
- Touch accounts you haven’t explicitly connected
A personal agent you don’t have to trust with the cloud.
Join the private beta and keep your day — and your data — to yourself.
Read the full Privacy Policy for the legal details and exact data scopes.