Shortly after birth, every child in Germany receives a vaccination card. Until adulthood, the WHO's yellow booklet should fill up to 13 vaccinations. But about 50% of the population lacks complete vaccination coverage. Most people are ready to be vaccinated, but the process is often not as easy as it should be. Often it is not known that or when one should be vaccinated. The app helps people to better understand their status and not to forget regular vaccinations.