Sleep tracking that tells you when it doesn’t know.
For iPhone.
Most sleep apps show you REM. None of them can measure it from a phone. Restwell reports what it actually observed, says so plainly when a night could not be measured, and never invents a number to fill the gap.
How it works
Restwell listens and feels for movement through the night, then scores sleep and wake using Cole–Kripke with Webster rescoring — the same published actigraphy methods used in sleep research, not a hand-tuned guess. Every score is broken down so you can see how each number was reached.
Your nights stay on your phone
No account. No server. Nothing to sign up for. Sleep data and audio recordings are stored on your device and never uploaded — there is nowhere to upload them to. See the Privacy Policy for exactly what that means.