VIATRA is an open-source model transformation framework based on the Eclipse Modeling Framework (EMF) and hosted by the Eclipse Foundation.
VIATRA supports the development of model transformations with specific focus on event-driven, reactive transformations, i.e., rule-based scenarios where transformations occur as reactions to certain external changes in the model.
Building upon an incremental query support for locating patterns and changes in the model, VIATRA offers a language (the VIATRA Query Language, VQL) to define transformations and a reactive transformation engine to execute certain transformations upon changes in the underlying model.