Why white noise calms a crying baby, and the app I built for 3am
I have two kids, so I have spent real time awake at 3am with a baby who will not settle. The thing that reliably works in that moment is not a clever technique, it is sound: a steady, boring whoosh that a screaming newborn will actually calm down to. I wanted a baby sleep app built around that one job, so I made one. It is called Dozy.
Why noise calms a baby
For nine months the womb was not quiet. Blood moving past the placenta is a constant, loud whoosh, and your baby slept, hiccupped and grew right through it. Then they are born into a silent nursery, and silence is the strange, alarming part. White noise, womb sounds and a heartbeat hand that constant back. It is less a trick than a reminder of the only place your newborn has ever known. That is why the vacuum-cleaner move experienced parents swear by works, and why a shush right by the ear can stop a cry mid-breath.
The 3am test
Most sleep-sound apps are built for an adult drifting off to rain. A baby app has different rules, and they all come down to one thing: you are using it half asleep, in the dark, with a baby in your other arm. So Dozy has big controls you can hit by feel, sound that fades in and out instead of snapping on, and a player that stays dark instead of lighting up the room. It keeps playing with the phone locked, and once the sounds are downloaded it works with no signal at all.
The sounds
The library is the part I most wanted to get right: womb sounds and heartbeat, the shusher and a vacuum hum, brown, pink and white noise for blocking out a slamming door or an older sibling, plus rain, ocean and fans for the nights those land better. Premium adds Mix Mode, where you layer a few of them into one blend and save it, because the exact combination that settles your baby is weirdly specific and you do not want to rebuild it from scratch every night.
Try it
Dozy is free and runs in 36 languages, no account required. The free version is ad-supported: unlock the premium sounds for a session by watching a short ad, or upgrade for the full library, Mix Mode, custom timers and no ads. If you are reading this at 3am with a baby on your shoulder, that is who I built it for.
Built at Appgineering, the studio I co-founded.