A detailed, well-presented sleep tracker for the Apple Watch — excellent if you are on iOS, irrelevant if you are not.
Best for iPhone and Apple Watch owners who want detailed, well-presented sleep analysis.
Pillow is the sleep tracker built around the Apple Watch. Worn overnight, the watch lets it track automatically and in detail, and the app turns that into genuinely useful, well-presented analysis. It is also one of the easier sleep apps to navigate — but it is iOS-only.
How we tested: Evidence-based assessment — from public information, app-store data and independent 2026 reviews. Not based on a long hands-on trial by ONDA.
Automatic tracking via the Apple Watch heart-rate sensor and accelerometer — more precise than a phone on the nightstand.
Wind-down content
5.5
Minimal — a measurement app, not a fall-asleep aid.
Sleep science
6.5
Sound staging and timing, without a distinctive science-led method of its own.
Insights and guidance
8.0
Every metric opens into weekly, monthly and yearly views; metric comparison helps explain a bad night.
App experience
8.0
Clear and genuinely easy to navigate.
Free tier
6.0
A freemium app — the fuller feature set needs the subscription.
Value
6.5
A subscription on top of needing an Apple Watch and iPhone narrows who it pays off for.
Pros
+Detailed, accurate Apple Watch tracking
+Well-presented analysis with weekly to yearly views
+Metric comparison to explain a poor night
+Easy to navigate
Cons
−iOS only — no Android
−Leans heavily on owning an Apple Watch
−Minimal wind-down content
−Fuller features need a subscription
Price: $50 per year (Premium); iOS and Apple Watch only (as of 2026-05-16)
Where it leads
Pillow is the sleep tracker built around the Apple Watch. Worn overnight, the watch lets it track automatically and in more detail than a phone on the nightstand, and the app turns that into genuinely useful analysis — every metric opens into weekly, monthly and yearly views, and you can compare metrics to work out what wrecked a particular night. It is also one of the easier sleep apps to navigate.
Where it falls short
It is iOS-only, and it leans hard on the Apple Watch — without one you lose much of what makes it good. Wind-down content is minimal; this is a measurement app, not a fall-asleep aid. And the fuller feature set sits behind a subscription.
Who it is for
Choose Pillow if you are on iPhone, wear an Apple Watch to bed, and want detailed, well-presented sleep analysis. Android users, or anyone without a watch, should look elsewhere.