Ripple is a relational, stack-based dataflow language for the Semantic Web. The Ripple project started out as a proof of concept for the annual "Scripting for the Semantic Web" challenge at the 2007 European Semantic Web Conference, and has gone on to become a versatile framework for traversal-based algorithms on semantic networks. The open source Ripple implementation is written in Java and includes a command-line interpreter as well as a query API which interoperates with Sesame 2.0.