Kosmtik

Kosmtik is an open-source development environment for creating and testing cartographic styles for Mapnik-based rendering, commonly used with OpenStreetMap data. It provides a local workflow that enables designers to iterate on map aesthetics with immediate visual feedback.

The tool runs as a Node.js application and serves a lightweight web interface for editing style definitions and previewing maps in real time. The editor focuses on how map features are drawn, including layer organization, color schemes, typography, and data sources, allowing cartographers to experiment with different rendering ideas quickly.

Kosmtik can connect to local data sources such as PostGIS databases and can work with MBTiles or other local data formats to preview tiles as styles are developed. This makes it convenient to test how a design will look with actual data before deployment.

For rendering and preview, Kosmtik serves test tiles rendered by the underlying Mapnik-based engine and provides an in-browser map viewer for navigation across zoom levels. This setup helps users assess styling consistency and readability across scales.

In practice, Kosmtik is commonly used in OpenMapTiles workflows and by developers seeking TileMill-like styling with modern Mapnik backends. It is maintained by the open-source community and is installable via standard Node.js package management workflows.

Kosmtik is a development tool rather than a full production tile server; while it can integrate into broader tile-serving stacks, its primary purpose is design, testing, and iteration of map styles in a local environment.