Scalarr is an innovative, Machine Learning based anti-fraud solution that detects the mobile app install fraud with dramatically improved accuracy. There are a lot of different types of app install ad fraud, although the traditional rules-based analysis used by existing solutions helps to detect only few of them. By applying to both unsupervised and semi-supervised machine learning algorithms, Scalarr solves the problem by analyzing deeply hundreds of features and variables, thus reducing efficiently the number of false positive and false-negative errors. With its unique self-learning engine it helps mobile advertisers to stay ahead of fraudsters without any need to update constantly the rules, as they modify their attack techniques.