kroki

Kroki is an open-source diagram rendering service that provides a lightweight HTTP API for converting text-based diagram descriptions into raster or vector images. By delegating the rendering to multiple diagram engines, Kroki enables users to embed diagrams in documentation, wikis, issue trackers, and websites without depending on local toolchains.

Supported languages include PlantUML, Graphviz DOT, Mermaid, Vega and Vega-Lite, and Ditaa, among others. The server can render outputs in formats such as PNG and SVG, which are easy to embed in documents or web pages. Kroki can be deployed as a standalone service and is distributed as a Docker image, making it simple to run on personal servers, cloud VMs, or within Kubernetes clusters.

Clients interact with Kroki through its REST API. Typical usage involves sending POST requests with the language path and the diagram source in the request body; the service returns the rendered image or a URL to the image depending on configuration. Kroki can be integrated with static site generators, documentation platforms, chat tools, and CI pipelines to generate diagrams on the fly.

Development and maintenance are community-driven; Kroki is actively developed with contributors adding new language renderers and improving performance and security. The project emphasizes portability, privacy, and the ability to host diagrams locally or in private environments. See also related diagram languages such as PlantUML, Mermaid, and Graphviz.