JupyterHub (and its predecessor, Jupyter Notebook) is an open source tool that combines live code and a presentational side. Over 100 languages are supported (notably Python, R, Java, Julia, Scala), the code can be divided into cells and accompanied by commentary formatted with Markdown, HTML, LaTeX, etc. JupyterHub Notebook is frequently used for data cleaning, exploration, analysis and visualization, statistical modeling and simulations. Graphical widgets can be used to easily enable user interaction with the code samples. The notebooks are run on a server, but accessed via browser, so no special tools are required on the user side. Since the notebooks can be shared with multiple users, they are also suited for collaboration. Notebooks can also be shared in a view only state with rendered graphics on the internet, with code kernel inaccessible to the viewer (e.g. to prevent the viewer from executing malicious code on the server). Notebooks can also be viewed without executing code using e.g. GitHub or NBViewer.