Everything stays with you. The app has no account system, no analytics SDK, and no advertising identifier, and nothing is sold. The app does not send data to us automatically: the only transmission to us happens when you press Send on a feedback or bug report in Support. Separately, Apple services may sync Health records, trial status, purchases, and device backups according to your own Apple Account settings, and copies you export or share yourself go where you send them.
When you choose to contact us from Support, your message, the app version, and the reply email you optionally provide are sent over an encrypted connection to a server we operate. That server stores nothing itself; it emails the report to our support mailbox, which is hosted on Gmail, where the report stays while we handle it and is then deleted, no later than twelve months after it arrives. Your connection's network address is used only to limit abuse, held briefly in the server's memory, and never stored or included in the email. A bug report can also include the app's diagnostic log if you leave that switch on; the log lists technical events such as alarm times, sleep session timing, tracking status, and error messages, and never contains recordings, your Apple Health records, or anything you typed. You can read exactly what it would send, or turn it off, before sending.
Sleep data - nights, movements, scores, tags and comments - is stored on your device. The app does not sync sleep data through CloudKit or iCloud. Nights you track are written to Apple Health with your permission; Health is Apple's own system and follows your Health sharing settings, which is also how your history reaches your other devices. Like any app's local data, the database can be carried in your encrypted iPhone backup, including an iCloud device backup if you use one; that backup belongs to you and follows your Apple Account settings.
Noise analysis measures loudness on the device; measurements are audio-free. If you separately enable Record snoring, short clips of detected sounds are saved on this iPhone only, capped per night, and deleted after a week; the cleanup runs whenever the app is used, so clips can outlast the week only while the app stays unopened. You can delete them all at any time in Settings. Recordings never leave the device.
With your permission, nights are written to Health, and overnight heart rate and breathing measured by your devices enrich each night. Health data is read and written only on-device under Apple's HealthKit rules.
One thing lives in iCloud key-value storage, and it is not sleep data: the free preview's start date and night count are kept there, tied to your Apple Account, so deleting and reinstalling the app cannot restart the preview.
Microphone and motion access are requested only when the feature that needs them is turned on. Notification and alarm permission are requested once after setup, because alarm reliability depends on them. Each can be revoked in iOS Settings at any time.