I live in Germany. I am also a parent. Every child born here comes home from the hospital with a small yellow booklet called the Kinderuntersuchungsheft. It is the official record of every U-Untersuchung from U1 at the maternity ward to U9 around age five. You carry it to every pediatrician appointment. Every vaccination gets a sticker. Every checkup gets a stamp. For those first years, that booklet is the most important paper document your family owns.

I kept forgetting it at home.

I built Kinderuntersuchungsheft because the paper one refused to stay in my diaper bag.

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The diaper-bag problem

The booklet is supposed to live in the diaper bag. In practice it rotates. Sometimes it is on the kitchen counter because one of us pulled it out to double-check a vaccination date. Sometimes it is in my partner’s bag. Sometimes it is in the jacket I wore to the last appointment and then never put back on.

You only notice it is missing when you are already at the Kinderarzt, five minutes late, holding a toddler who has chosen this exact moment to renegotiate the concept of shoes.

The pediatrician asks what was logged at the last visit. You pat every pocket. You text your partner. The booklet is at home on the counter.

What existed

Nothing, really. The Kinderuntersuchungsheft is a federal document. It is issued by the G-BA, it is in German, and the paper booklet your pediatrician signs is the legal record. No hospital hands you a digital copy.

I looked for apps anyway. The closest ones were generic vaccination trackers from pharmacy chains. They did not cover the U-Untersuchungen, did not speak the G-BA format, and most of them wanted me to create an account to see a blank form. Some wanted an email for a newsletter. A few wanted both.

I did not want to create an account to log that my child now weighs 6 kg.

What I actually wanted

Five things:

1. Every page of the yellow booklet, fillable per child, on my phone.
2. The STIKO vaccination calendar, pre-seeded from my child’s date of birth.
3. A growth chart for weight, height, and head circumference, plotted across every U-exam.
4. Local reminders a few days before each exam window so we do not miss the slot.
5. No account, no server of mine, no analytics.

None of the existing apps did all five. So I built one.

How it works

Four steps:

1. Add your child’s name and date of birth. The app seeds every U-Untersuchung on the correct timeline.
2. Fill in the pages as you go. At the pediatrician. On the U-Bahn on the way home. Before the next appointment.
3. Tick off vaccinations as they happen. The STIKO calendar keeps the next dose in view.
4. Get a local reminder a few days before each exam window. Bring the phone. Done.

Multiple children get multiple schedules. Switch between siblings with a tap. iCloud keeps the whole thing synced across your iPhone, iPad, and Mac, encrypted end-to-end by Apple.

The paper booklet is still the paper booklet

This was the first rule I set for myself. The app does not replace the Kinderuntersuchungsheft. The pediatrician still stamps, signs, and writes in the paper one. That remains the legal record. The app is a parallel copy you control: easier to search, never lost in the jacket pocket, always with you.

If you hand the phone to the Kinderarzt, they will not sign it. That is fine. It was never the point.

What I deliberately did not build

The “no” list is long here too.

• No account, no sign-in, no email capture. Data lives on your iPhone and syncs only through your private iCloud.
• No analytics, no tracking, no third-party SDKs. Apple’s App Privacy label reads “Data Not Collected,” and that is also the literal truth.
• No subscription. One App Store purchase, every child you have, forever.
• No cloud of mine. I do not see anyone’s health data and I do not want to.
• No social features. Your child’s U-exams are not content.

Every one of those is a standard playbook move that would have made the product worse for a parent.

Ten languages

The app ships in German, English, Turkish, Russian, Arabic, Polish, Ukrainian, Romanian, Spanish, and Brazilian Portuguese. Germany has a lot of parents who did not grow up in German. The official booklet is in German only. When the Kinderarzt asks you about Anamnese and you are already tired, reading your own language helps.

The German medical terms stay visible alongside every translation, so you can still follow what is being written into the paper booklet.

Who it is for

Any parent in Germany with a yellow booklet somewhere in the diaper bag. If you have ever stood at the Kinderarzt patting every pocket, this is the app I built for you.

Try it

Kinderuntersuchungsheft is on the App Store.

One purchase, every U-Untersuchung, every STIKO vaccination, every child. Works with Family Sharing, so the other parent gets it on their phone too.