The short version: your health data never leaves your iPhone. Here's the long version.
On your device, nowhere else
Everything Migraine Sentry knows about you (attacks, health signals, baselines, learned triggers) is stored in a local database on your iPhone. There is no account, no cloud sync, and no Migraine Sentry server that holds your health data.
The one thing that leaves your phone
To fetch local weather and pressure forecasts, the app sends your approximate location, rounded to about 1 km, to a weather data provider. No identifier, no health data, nothing else travels with it. That's the entire network footprint of your personal data.
Permissions, and what they actually do
| Permission | Used for |
|---|---|
| Health data | Reading signals Apple Health already records. Migraine Sentry never writes to or shares your Health data. |
| Motion & barometer | Your iPhone's pressure sensor. |
| Location | Approximate position for the weather lookup above. Never stored precisely. |
| Notifications | Morning forecasts, signal nudges, and check-in / follow-up reminders. Never marketing. |
Deleting your data
Settings → Delete all data permanently erases every record after a confirmation (you'll be asked to restart the app). Because your data only ever lived on your device, deletion is genuinely complete; there's no server copy to chase.
Full details: Privacy policy.