Yakindu SCT is a modular toolkit for model-based development of embedded systems using statecharts. It includes editors for graphical and textual statechart modeling, a simulator for testing statecharts, and code generators for languages like Java and C++. The toolkit is extensible and customizable, allowing for the integration of domain-specific concepts into statecharts for domains like human-machine interfaces. This is demonstrated through an example of adding concepts from an HMI domain meta-model, like widgets and animations, as first-class elements in statechart declarations and expressions.