Your baby is already telling you. Ninu helps you listen.

We don't publish an accuracy number, and that is deliberate. Any figure we could quote would come from public research recordings that sound nothing like your nursery at 3am, and putting it on a page would imply a precision that no cry classifier currently has. What we publish instead is the method — three five-second clips, three models soft-voting over 126 acoustic features, then your care timings — and, on every single result, the confidence percentage and how many of the three clips agreed. If Ninu isn't sure, it says so and shows you the runner-up. Treat it as a well-informed starting point, not a verdict.

Yes, and there is nothing to switch on. The models are bundled inside the app and run on the device's own processor, so a full analysis works in airplane mode, on a plane, or in a hospital basement. The only thing Ninu ever needs a connection for is checking your subscription, and even that is cached, so a cold launch with no signal opens straight into the app.

No. Each five-second clip is classified and then deleted within seconds. What is kept on your device is a spectrogram image and a one-line description of the sound, such as “High-pitched, loud, rhythmic cry” — the recording itself is gone. There is no server of ours that could receive audio even if the app tried to send it, because there is no server.

Hungry, tired, belly pain, discomfort, and needs to burp. Each result comes with what that kind of cry usually sounds like and one specific thing to try — a feed, a swaddle and dim lights, bicycle legs, a diaper and clothing check, or an upright burping position. Ninu classifies into these five and nothing else; it does not attempt to detect illness, pain levels, or anything a doctor would diagnose.

A single noisy five-second recording can fool any classifier — a passing truck, a sibling, an extractor fan. Ninu records three clips back to back, runs each through the models, and averages the probabilities rather than taking a simple majority, so a confident model and a hesitant one do not count the same. Agreement across three clips is much harder to produce by accident than agreement with one.

Every result shows a string like 3/3 or 2/3. It counts how many of the three clips independently landed on the answer Ninu is showing you. 3/3 means all three agreed, and 2/3 means one dissented. If all three disagree, Ninu marks the result uncertain rather than picking a winner. It is shown because the disagreement is information you should have, not something to launder behind an average.

Ninu keeps a running clock on the last feed, the last nap and the last diaper change, and those clocks re-weight the classifier's output before it is shown to you. A feed under fifteen minutes ago multiplies “hungry” by 0.4; over two hours ago multiplies it by 1.2. A nap under thirty minutes ago multiplies “tired” by 0.3, and four hours awake multiplies it by 1.4. All five confidences are then renormalised, and the result tells you which clock moved it. If you have logged nothing at all, no weighting is applied.

No — Ninu is complete on the iPhone alone. If you do have one, the Watch app is included in the subscription at no extra cost and does the full job on the wrist: three clips, the answer, and a care log entry, without the phone. It also adds a Smart Stack widget and complications in circular, corner, inline and rectangular sizes.

Purchases can only be made on the iPhone, because subscription identities are per-install and a purchase made on the Watch could never be matched to the one on your phone. Subscribe on the iPhone, then open Ninu on the phone with the Watch unlocked and nearby — the entitlement transfers directly between the two devices. If the wrist still says “Subscribe on iPhone to unlock”, open the phone app once while both are in range.

No. Ninu is subscription-only at $3.99 a month or $19.99 a year, and the annual plan starts with a 3-day free trial for Apple Accounts that have not used the offer before. A free tier here would have to be either a worse classifier or a listen counter, and a parent at 3am with two listens left is being sold anxiety at the moment they are least able to refuse. The trial is the whole app instead.

Cancel in Settings › [your name] › Subscriptions on your iPhone. It is Apple's flow rather than ours, and access continues to the end of the period you have already paid for. Nothing on your device is deleted when a subscription lapses — your history and care log stay exactly where they are, hidden rather than erased, and reappear in full if you subscribe again.

No, and that is a design choice rather than a limitation waiting to be fixed. Ninu records only when you tap, only for fifteen seconds, and only while the app is open. It is not a baby monitor, it does not run at night on its own, and it never has the microphone open when you have not asked it to. If you want a room monitor, buy a room monitor.

Before classifying, Ninu passes the clip through Apple's own sound-recognition system to confirm it actually contains a baby crying. If it doesn't, Ninu says “No baby cry detected” instead of guessing at whatever it did hear. Move closer — arm's length is about right — pause a fan or a white-noise machine if one is running, and record while your baby is actually crying rather than settling.

Thirty days, shown on the device and used to build the insights. Older entries are hidden rather than deleted, so nothing is lost if a subscription lapses and later resumes. Everything lives in the app's own storage on the phone that recorded it: there is no cloud sync and no copy anywhere else, which also means deleting the app deletes all of it permanently.

No. Ninu is an assistive tool for tired parents and it does not diagnose anything. It classifies a sound, offers a likely explanation, and attaches a confidence to it — and it is sometimes wrong, which is exactly why it shows you the confidence and the clip agreement rather than a single confident word. If your baby seems unwell, is crying inconsolably, has a fever, or has any difficulty breathing, call your pediatrician or your local emergency number.