AutoSleep by Tantsissa is one of the most respected apps in the Apple Watch ecosystem. It tracks sleep stages, calculates a readiness score, and gives you a detailed breakdown of your night's recovery. For about $5.99 one-time at the time of writing, it is arguably the best value in health tech.
ARC: Circadian Rhythm Tracker is an iPhone app with no hardware requirement. It identifies your chronotype through a 22-step setup, lays out your day, and tracks the two things a wearable can't see: what you drank and when you got outside. Disclosure: we make ARC.
These two apps do not compete. They complete each other.
What AutoSleep Gets Right#
AutoSleep is excellent at the retrospective question: how did I sleep? Its sleep staging (light, deep, REM) is accurate enough for most non-clinical purposes, and the readiness score — based on HRV, resting heart rate, and sleep quality — gives you a reliable sense of your recovery status each morning.
For Apple Watch users who want a detailed sleep report without buying a ring (see Oura Ring vs ARC), AutoSleep is the answer. It sits quietly on your wrist all night and generates a comprehensive morning report.
The Gap AutoSleep Cannot Fill#
AutoSleep stops when you wake up. It has no protocol for what comes next.
It does not know your chronotype. It cannot tell you that as a Wolf, your peak focus tends to land in the late afternoon or early evening rather than at 9 AM (a typical estimate; yours may differ). It has no caffeine tracker, no morning light timer, no daily plan that adjusts after a short night.
A readiness score of 68 tells you that you slept reasonably well. It does not tell you when to drink your first coffee, what time to schedule your deepest work, or how to recover from your below-average sleep without destroying tomorrow's rhythm too.
What ARC Adds to the Picture#
ARC picks up precisely where AutoSleep leaves off.
Each morning you can log last night's sleep in one tap, however the sensors scored it. (ARC doesn't read Apple Health or your Watch, so this is your own call.) A short night starts ARC's sleep-debt recovery loop, which changes the day's sentence, the one ask and your caffeine cutoff for the next few days.
The 20-minute light timer runs on your Lock Screen while you're outside. The caffeine tracker logs every drink and shows your active mg, your decay curve, and your last safe coffee — the exact thing AutoSleep cannot calculate because it does not know when you had coffee. (Try the math for one cup in the free caffeine calculator.)
Notifications for your coffee window, caffeine cutoff and wind-down are timed to your Lion, Bear, Wolf, or Dolphin schedule.
The Ideal Stack#
For Apple Watch users who want the complete circadian picture:
AutoSleep at night → measure your sleep quality and HRV recovery.
ARC during the day → follow a day plan built around your chronotype and last night's sleep.
Together they cost about $46 for the first year: AutoSleep once, plus ARC's annual plan. And they cover ground that neither app could cover alone.