Data visualization is integral for exploratory data analysis and data presentation. Consequently, every programming environment suitable for data analysis needs a feature-rich visualization library. In this paper, we present Plotly.NET - a fully featured charting library for the .NET ecosystem. Plotly.NET requires little ceremony to use, provides multiple API (application programming interface) layers for both low-code and maximum customizability, and can be used in many different visualization workflows - from interactive scripting and notebooks to user interface applications. Plotly.NET brings the charting capabilities of plotly.js to the .NET ecosystem, successfully combining the flexibility of the plotly grammar with the type-safety and expressiveness of .NET.