Effective July 11, 2026 · Published by AuraByte Studios
Not medical advice
Vellum provides cycle predictions for personal reference and is not medical advice or a contraceptive method. Do not rely on Vellum to prevent or achieve pregnancy or to diagnose any condition.
What we collect
Nothing about you. Vellum has no accounts, no sign-in, no analytics SDKs, no advertising SDKs, no crash-reporting service, and no server-side telemetry. No personal information, contact details, location, device identifiers, or usage events leave your device. Vellum's own application code makes no network calls; the transitive Expo modules the app is built on were not exhaustively audited for background telemetry, so we scope this to Vellum's own code.
What stays on your device
Everything you log — cycles, day-by-day flow level, symptoms, mood (1–5), energy (1–5), sleep hours, sexual activity type, discharge type, basal body temperature, medications, and notes — is stored in a SQLite database file (vellum.db) inside the app's sandbox on your device. Your profile row (average cycle length, period length, goal) and your app settings (theme, units, locale, app-lock preference, reminder preferences) are stored the same way. Uninstalling the app removes all of this data.
The on-device database is not currently encrypted at the file level. It is protected by the operating system's app sandbox and, when you enable it, by App Lock (Face ID / Touch ID / device passcode). On first run, Vellum generates a random 32-byte key and stores it in the system keychain (iOS Keychain / Android Keystore) for a future at-rest-encryption feature; in the current build that key is stored but not yet used to encrypt the database.
HealthKit / Google Fit / Health Connect
Not used. Vellum does not read from or write to Apple HealthKit, Google Fit, or Android Health Connect. There is no HealthKit entitlement and no health-data usage description in the app.
Permissions we request
Face ID / Touch ID / device passcode (iOS & Android): to lock the app so your cycle data isn't visible if someone else picks up your device. Biometric authentication is handled entirely by iOS or Android; the app only receives a success/failure result — it never receives your face or fingerprint template.
Notifications (iOS & Android): only requested if you turn on a reminder. Period, fertile-window, ovulation, and daily-check-in reminders are scheduled locally on your device from your cycle prediction. There is no push server and no push token registered.
On Android, the manifest also declares INTERNET (the React Native / Expo default — no app code opens a socket), VIBRATE (haptics), and the biometric permissions. The overlay permission (SYSTEM_ALERT_WINDOW) and the legacy external-storage permissions are explicitly blocked from the shipped build via the app's blockedPermissions list, because Vellum has no overlay UI and uses the platform Storage Access Framework for export and import.
Vellum does not ask for your camera, microphone, photos, contacts, calendar, location, HealthKit / Google Fit / Health Connect, motion data, or Bluetooth.
Network usage
None from Vellum's own code. A recursive source review of the app for fetch(, axios, XMLHttpRequest, WebSocket, and hardcoded HTTP(S) URLs returns zero results in application code. Over-the-air JavaScript updates are explicitly disabled in the build configuration. Fonts referenced by the app are bundled into the binary, not fetched at runtime.
Export, import, and delete
Export writes a JSON backup (or a CSV of your day logs) to your device's cache folder and hands it to your system share sheet; the cache file is deleted after you finish sharing. Import lets you pick a JSON backup with your device's file picker; the file is validated against a strict schema before it replaces any local data. Delete-all wipes your profile, cycles, day logs, settings, and any leftover export files inside the app sandbox.
Widgets
The iOS widget reads a small snapshot (cycle day, phase, days-until-next-period) from an App Group shared preference (group.com.vellum.app). The Android widget reads the same snapshot from local AsyncStorage. Widget data never leaves your device. Note that a home-screen or lock-screen widget shows your cycle day without unlocking the app — if you'd rather not surface it, don't add the widget.
Law-enforcement requests
Because Vellum stores your cycle data only on your device and AuraByte Studios never receives it, we have nothing to hand over in response to a subpoena, warrant, or other lawful-access request. The only copy of your data is the one you hold.
Children
Vellum is a cycle-tracking app intended for people who menstruate and is not directed at children under 13. We do not knowingly collect any data from anyone, including children.
Contact
Questions or requests: support@aurabytestudios.online. The full policy is also published at this page.