The free to use, open source toolkit YAKINDU Statechart Tools (SCT) provides an integrated modeling environment for the specification and development of reactive, event-driven systems based on the concept of statecharts. Editing Yakindu Statechart Tools (SCT) feature an intuitive combination of graphical and textual notation. While states, transitions, and state hierarchies are graphical elements, all declarations and actions are specified using a textual notation. The usability of the statechart editor is optimized for working with these statecharts. Validation The validation of statecharts includes syntax and semantic checks of the complete state chart. Examples of validations are the detection of unreachable states, dead ends, and references to unknown events. These validation constraints are live checked during editing. Simulation In addition to the structural validation, checking the dynamic semantics is crucial. It is not possible to determine the correctness of a statechart just by visual examination. Thus, the user must be able to execute the statecharts he is working on. The integrated statechart simulation engine addresses these needs. The user can execute statecharts directly within the modeling environment. Active states are directly highlighted in the statechart editor and a dedicated simulation perspective features access to execution controls (start, stop, pause, resume), inspection and setting variables, as well as raising events. Code Generation Yakindu Statechart Tools (SCT) includes code generators for Java, C and C++. The code generators follow a ‘code-only’ approach and do not rely on any additional runtime library. The generated code provides a well-defined interface and can be integrated easily with any client code. The generated code is also readable and structured in such a way that allows for very effici