With almost 3.8 million customers in around 90 of its own online shops, Prindo is the second largest online provider of printer accessories in Europe. The aim of the project is to better understand customers based on data. The aim is to analyse which customer types and which behavioural patterns can be identified. It is also important to find and create an identification pattern for similar customers and a merge logic of matching customers. The customers should be better understood on the basis of the data. In the second part of the project, it should be possible to develop fraud prevention measures.