Measuring software internal quality is still a mystery, even though many source code metrics have been around for years. The problem with those metrics is they usually only capture one aspect of quality. We must consult many metrics to come to a conclusion about the overall quality of our code. Sonar is an integrated tool for checking, tracking and visualizing those metrics. It not only combines metrics together, but also mixes them with historical measures, giving us a better insight into the internal quality of the codebase.