how can I help
Safe listening first, because that's the one that really matters. Then the questions I actually get asked, then everything this app leans on so you can read it yourself. If none of it helps, there's a form at the bottom and it comes straight to me.
read this first
Sound machines can be played loudly enough to matter. In a 2014 study in Pediatrics, researchers measured fourteen infant sleep machines at maximum volume. All fourteen exceeded 50 A-weighted decibels at 30 cm, the level recommended as a ceiling for hospital nurseries, and three exceeded 85 dBA, which over an eight-hour night passes adult occupational limits for accumulated noise.
COO is a comfort tool, not a medical device. It does not diagnose, treat or prevent anything. If your baby is inconsolable, feverish, or you are worried, call your pediatrician.
common questions
No. The 7-day trial takes no card and creates no subscription, so there is nothing to cancel and nothing that renews. When it ends, COO simply returns to the free version and your custom queue order is kept. If you want to keep Premium after that, it is a one-time $3.99, paid once, never again.
Tap the north star in the top corner of the app, or tap any locked playlist, then tap start 7 days free. The clock starts when you tap, not when you install, so you don't burn days before you know you have them.
Open the north star and tap restore purchase. That asks Apple for your purchase history and re-unlocks it. This happens most often on a new phone or after a reinstall. If it still doesn't unlock, message me below with the Apple ID email you bought it with and I'll sort it out.
Across the room, never in or on the crib, at a volume you can comfortably talk over. That single choice matters more than any setting in the app. The reasoning, and the paper behind it, is in the safe listening box at the top of this page.
Free gives you four of the six playlists and 3-minute sessions. Premium adds Teething & Comfort and Sleep Wind-Down, the sound mix controls, 15 and 30 minute sessions, Play All, and a custom queue order.
Yes. Every sound file ships inside the app, so COO works fully offline on a plane, in a car, in a basement. It only needs the network to verify a purchase.
Yes. COO declares background audio and keeps the audio session alive, so you can lock the phone, put it face down across the room, and it keeps going. It also appears on your lock screen so you can stop it without unlocking.
It was built for newborns through toddlers, and honestly a fair number of adults use it on themselves. The premise is co-regulation, which means it is at least as much for the person holding the baby as for the baby.
You can. I'd rather you didn't at volume, though. The safety research above is about continuous, all-night, close-range exposure. A session that fades out, kept low, with the phone across the room, is how I'd do it.
There is no login, no account, and no profile. COO doesn't ask for your name, your email or your baby's details, and there's no server for it to send them to. Your trial date and your queue order are stored on your own device. Purchases are handled by Apple and by RevenueCat, which is what tells the app whether you own Premium.
Refunds for App Store purchases are handled by Apple, not by me. Go to reportaproblem.apple.com, sign in, find COO, and request a refund. If Apple declines and you think that's wrong, tell me below and I'll help however I can.
Not yet, it's iOS only. If you want it on Android, say so in the form below. I'm one person deciding what to build next, so that genuinely counts.
where this comes from
Some of what COO is built on has been measured in a lab. Some of it has been practiced by people holding babies for as long as there have been babies to hold. Both are real, and some things are real well before the instruments arrive to describe them. They are different kinds of evidence though, so I've kept them apart rather than blur them together, and told you which is which.
What has been measured
The premise of the whole app: a settled adult nervous system helps an unformed one find its footing.
Why the noise layers are shaped the way they are, and where the decibel figures come from.
The evidence that these particular sounds do something, and how large that something is.
Where the evidence is genuinely mixed, and I'd rather say so than only show you the flattering studies.
The single most important paper on this page.
What has been practiced
The oldest evidence there is, and the kind a randomised trial cannot produce.
Older than people assume in one way, and much younger in another. Both worth knowing.
it comes to me, not a queue
Bugs, refunds, a playlist you wish existed, or the thing that finally worked at 4am and you want to tell somebody. I want all of it.