Three ways your journal can think — one promise that never changes.
Choose how much of the thinking happens on your phone, and how much you hand off — and to whom.
On-device AI
Everything happens on your phone.
Mood and energy analysis runs with Apple's Foundation Models, directly on your iPhone. Speech becomes text with Apple's on-device SpeechTranscriber — or, if you choose, the downloadable Whisper model, running on the Neural Engine. Nothing leaves your phone, it works without a connection, and it's free forever.
No account, no server, no signal required.
Cloud AI, your key
Bring your own key, keep the control.
Prefer a cloud model? Connect your own OpenAI or Mistral API key and Cairn calls that provider directly — sending only the entry text needed for analysis or transcription. You see the costs, you hold the key, you can revoke it any time.
Keys live in the iOS Keychain. Cairn's servers never see them.
Managed AI · Pro
Or let Cairn hold the keys.
Pro routes cloud analysis through Cairn's managed proxy — we hold the provider keys, not you. Every request is verified with Apple App Attest, and your entry text is processed only for that moment: never stored, never used to train anything. Try it in full for 7 days.
We ask before any entry ever reaches the cloud.
Your data, always
Your journal stays yours.
Entries live in a local database on your device, never on Cairn's servers. Optional iCloud sync (Core and up) stays inside your own Apple account — Cairn never stores it or reads it. Heart rate, HRV, and daylight context never leave your phone either. Export everything, or delete it all, whenever you want.