Preswald

Preswald is a framework for building interactive data applications that run entirely in the browser as static sites. It allows developers and data practitioners to write pure Python code that is compiled into self-contained web apps, eliminating the need for managing servers, backends, or traditional deployment pipelines. The primary purpose of Preswald is to simplify the creation and distribution of data-driven tools, dashboards, and visualizations while maintaining a familiar Python-based workflow.

The tool supports interactive UI components, reactive behavior, and dynamic visualizations directly from Python, enabling rich user experiences without JavaScript. Because the output is a static site, Preswald apps can be hosted on any static file host (e.g., GitHub Pages, Netlify, S3) with minimal configuration. It is designed to integrate naturally with common data and scientific Python libraries, making it straightforward to connect data transformations, plots, and controls into a cohesive interface. The static architecture also improves performance, portability, and security by avoiding runtime server dependencies.