Sourcetrail is an interactive source explorer that simplifies navigation in existing source code. Sourcetrail currently supports the languages C/C++ and Java. Much of the UI design is therefore based on these languages and might change as soon as other languages are supported. Sourcetrail’s aim is to give answers to all your questions about your source code. Sourcetrail first indexes your code and gathers data about its structure and then provides you a simple interface consisting of three interactive views, each playing a key role in getting information. SourceTrail is free for non-commercial usages.