Bokeh server is a system for using the Bokeh Application Programming Interface (API) and associated tools in order to be able to modify what gets plotted and how data are plotted, as well as to leverage Graphical User Interfaces (GUIs) to customize data analyses and visualizations. Bokeh server allows one to write Python callback functions that respond to user interactions in order to modify plots and data analyses. The same Bokeh server code can be used by a single person running in a local browser, or by an organization to serve up visualization applications on the Internet through a public webserver. As such, Bokeh server can support the deployment of rich data dashboards to support a number of data analysis and visualization tasks.