Daybook AI (“the app”) is published by EScience Apps. This policy describes what data the app handles and where it goes. The short version: your data stays on your device.
What the app accesses
Calendar (READ_CALENDAR / WRITE_CALENDAR). Daybook reads and writes the calendars already stored on your device (via Android’s Calendar Provider) so you can view, create, move, and delete events. Calendar data is processed on your device only.
Reliable sync — Google Calendar API (optional, off by default). If you turn on “Reliable sync” and link a Google account, Daybook uses the Google Calendar API (the https://www.googleapis.com/auth/calendar scope) to keep your calendar events in sync directly between your device and Google — reading your events and writing the events you create, edit, move, or delete in Daybook. This sync runs directly between your device and Google’s servers under your own Google account; the event data is never routed through, copied to, or stored on any Daybook / EScience Apps server — none exists. You can unlink the account or turn Reliable sync off at any time in Settings, and you can revoke Daybook’s access in your Google Account permissions.
Contacts (READ_CONTACTS). Daybook reads your device contacts — names, phone numbers, birthdays, and anniversaries — to show birthdays on your calendar, autocomplete names, and build each person’s timeline. Contact data is processed on your device only and is never uploaded anywhere.
App-created data. Call logs, notes, tasks, promises, and relationship metadata you create in Daybook are stored in the app’s local database on your device.
Notifications (optional, off by default). If you grant notification access and choose which apps to listen to, Daybook reads those apps’ notification text to spot appointments (“dentist Tuesday 3pm”) and suggest them as calendar events. Notification text is analyzed entirely on your device, stored only in the app’s local database, and never uploaded. Suggestions are added only when you tap Add.
Shared content (only when you share it). When you use Android’s Share menu to send a message, email, or screenshot to Daybook, that content is processed on your device to propose a calendar event, and goes nowhere else.
What the app does NOT do
No account or sign-up. The app has no server; nothing is synced to us.
No analytics, tracking, or advertising SDKs.
No sale or sharing of personal data with anyone. We never see your data at all.
On-device AI (the default)
Daybook’s default AI assistant is a small language model that runs entirely on your phone (via Google’s MediaPipe LLM Inference). Installing it is a one-time download of the model file (about 550 MB) from a public model repository (Hugging Face). That download carries none of your data. After it, every AI feature runs offline: no key, no account, no network, no cost.
Optional cloud AI (bring your own key)
Cloud AI is used only if you choose it and supply your own API key (Anthropic, OpenAI, or Google). When it runs, the minimum needed context is sent directly from your device to your chosen provider, under your key and that provider’s terms. It never passes through any Daybook server. Keys are stored in Android Keystore-encrypted storage and sent only to the provider they belong to. Disable cloud AI any time; the app stays fully functional on built-in on-device intelligence.
Google user data and the Google API Services User Data Policy
Daybook AI’s use and transfer of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements.
Specifically, for data obtained through the Google Calendar API:
Daybook accesses your Google calendar events only to provide and improve the calendar-sync feature you explicitly enabled (“Reliable sync”). It is used for no other purpose.
Your Google Calendar data is not transferred to any Daybook / EScience Apps server (there is no server), and is not sold, shared, or transferred to any third party.
Your Google Calendar data is not used for advertising, and is not used to train any generalized or third-party AI/ML model.
No humans read your Google Calendar data, except where you give explicit permission, for security purposes, or as required by law.
Data retention and deletion
All app data lives on your device. Deleting the app deletes the app’s own database and stored keys. Calendar events and contacts belong to your device’s system stores and the accounts that own them. You can revoke Daybook’s Google access at any time at myaccount.google.com/permissions.