The guide
The app answers in five seconds; this is the paragraph behind it, for whoever wants it at 2 a.m. What the water means, the science it stands on, and what your child's sleep can and cannot do at each age — so your expectations can change on the same schedule their biology does. Written by me, kept current, every claim traceable. The dated lab log lives in the notebook.
Philosophy
A tide, never a deadline every age
This app will never tell you your child has to sleep at 14:20. That is its founding rule, and everything else here is a footnote to it. The screen you look at is water — a tide of sleep pressure rising toward a shore — and the times it implies are wide, soft windows. Never appointments.
What this app will never do every age
NaniNani exists to lower a tired parent's stress, not to become one more thing you get graded on. That reads like a slogan right up to the moment a screen has to decide whether to show a countdown — so I wrote it down as rules a code review can fail against. This is the promise, in the form of eight things the app will never do to you.
The science
What sleep pressure actually is every age
Everything this app shows you rests on one piece of biology: sleep pressure. It is not a metaphor I invented for the app's tide — it is the best-established mechanism in sleep science, called Process S in the literature since 1982, and it is the reason "wake windows" work at all. If you understand this one idea, the whole app becomes obvious.
Using NaniNani
How to read the water every age
The home screen is a tide. The waterline is your child's sleep pressure — the real, physical drive to sleep — rising while they are awake, draining while they sleep, drawn against their own personal threshold: the level at which they, historically, fall asleep easily. The percentage riding the "now" line says how close the water is to that shore. 100% means "sleep would come fast now". It never means "they must sleep now". Nothing on this screen is a deadline; here is how to read it.
Hands-on
How to settle a newborn 0-8w · 2-4m
Here is the honest frame first: you cannot make a baby sleep. Nobody can — "you can force wakefulness upon sleep, but you cannot force sleep upon wakefulness," as Weissbluth puts it. What you control is the opportunity: catching the moment when pressure is high, then raising the level of soothing until staying awake becomes the hard option. Everything below is drawn from the two books this app is built on, and it is what my partner and I actually leaned on.
What to expect
Four to seven months 4-7m
This is the era when structure actually shows up — the one every schedule chart on the internet quietly assumes. Around four months, sleep architecture becomes essentially adult: sleep begins in deep non-REM, cycles maturely, and responds to timing. The day starts organizing around anchors, and for the first time, watching the clock becomes as useful as watching the child.
Seven to twelve months 7-12m
This is the most orderly stretch of the first two years — enjoy it. The day settles into a shape so common it's almost a uniform: wake around 6–7 a.m., nap near 9, nap near 1, bed between 6 and 8 p.m. By nine months, 91% of babies take exactly two naps, and the pooled reference data (Galland's systematic review) shows night sleep holding steady around eleven hours. If the first half-year was weather, this is climate.
The first eight weeks 0-8w
If your baby is under two months old, here is the single most useful thing I can tell you: the scattered, clockless sleep you are looking at is biology running exactly on schedule. Nothing is late, because the machinery that could be late has not switched on yet. This article is the reassurance most sleep apps know and don't say — they simply go quiet under two months and let you fill the silence at 3 a.m. with "my baby isn't doing the thing the app is waiting for."
The second year 12-24m
One thing dominates the second year: the move from two naps to one. It is the biggest, sloppiest transition in all of childhood sleep, and knowing its true shape spares you months of second-guessing. The headline numbers: at twelve months, 17% of children are on one nap; at fifteen months, around half; at eighteen months, 77%; by twenty-one months, 88%. The median lands near a year and a half. So if your friend's fourteen-month-old dropped to one nap and yours hasn't — both children are dead on schedule.
Two to four months 2-4m
Somewhere in these weeks, the clock switches on. The melatonin rhythm that simply didn't exist at birth becomes observable around nine to twelve weeks and steadies at thirteen to fifteen; body temperature and cortisol fall into daily rhythm; day and night become real categories for your baby, not just for you. This is the single fastest period of change in the whole first year — "the most rapid consolidation in infant sleep regulation occurs in the first four months" — and it changes what you can fairly expect, in stages, not all at once.
Two years and beyond 2y+
The nap is not over. That's the first thing to know, because around the second birthday almost every child stages a convincing performance of being done with it — and almost none of them are. At age three, 92% of children still nap; even at four, more than half do. The performance is boundary-testing, a toddler discovering that naptime is negotiable in a way gravity is not. The books' answer is the same calm one: keep offering the midday rest, unmoved, for about an hour. In most cases, after a couple of days of theater, the napping resumes as if nothing happened.