Python tools like Bokeh and Dash let you build custom Web-based interactive visualization apps and dashboards. While these solutions work well to visualize megabyte-sized datasets, web technologies struggle to render gigabyte or larger datasets efficiently, because they transfer all the data into the client browser. Pre-rendering the data on the server using a tool like Datashader can visualize such large datasets efficiently, but the resulting static renderings make exploring individual datapoints difficult. This talk demonstrates how the HoloViz ecosystem of tools (holoviz.org) allows you to run exploratory notebooks and build dashboards that do server-side rendering of billions of data points without losing the ability to interactively inspect and annotate individual samples in the browser.