The main thing is not behind a subscription
Predicting the next sleep is why both apps exist. In napnap it is free and nothing is held back for a paid plan, because there is no paid plan.
And it says what it still does not know
napnap shows what part of the forecast is your baby's by now and what part is still the table for their age. It is an uncomfortable number to put on a screen and it is the one that lets you decide whether to trust it today.
Fourteen days with a margin, not just the next sleep
The whole day and the two weeks after it, with the time they get up, the awake stretches between naps and bedtime. Every hour with its margin, and the night anchored to the household's clock instead of dragging the accumulated error.
And the food is in here too
napnap carries a catalogue of 92 foods for starting solids, written around a Mediterranean kitchen: rabbit, sardine, chard, curd cheese, paprika. It is one pantry and not a generic list, which is what makes an example meal look like something somebody would actually cook.
And the plan shares things out with a rule behind it: iron from the second week, at most two major allergens a week, and the waits by age checked on the server with their reason attached.