Project Jupyter has gained steady adoption for interactive computation and visualization in the context of Data Science and Machine Learning. During this workshop we will present - The Project Jupyter Notebook and the underlying protocol implementation - ipywidgets, the library that enables interactive widgets, from simple buttons & sliders to maps and 3D plots - xeus-cling, the interactive C++ kernel for the Jupyter ecosystem In the interactive part of the workshop we will walk through creating custom widgets for interactive data visualizations, and gain a deeper understanding of the traitlets protocol, which is used to synchronize data from C++ or Python to the JavaScript frontend.