What is Kroki! and what does it do?

Updated

Kroki! is an online service that creates diagrams from textual descriptions. Instead of drawing boxes and arrows by hand, you write a short text definition in a supported diagram language, and Kroki! renders it into an image. It is aimed at developers, technical writers, and anyone who needs diagrams that stay in sync with documentation or code.

How it works

The core idea is "diagrams as text." You provide a description using a syntax such as PlantUML, Mermaid, Graphviz, or another supported format, and Kroki! turns that description into a rendered diagram. Because the source is plain text, it can live in a README, a wiki page, or a docs repository and be version-controlled like any other file.

The site itself offers a Try section for experimenting, a Features overview, Examples, a list of Diagram types, and a Cheat sheet to help you get the syntax right.

What you can do with it

  • Generate diagrams without drawing tools. You describe the structure in text and get a diagram back.
  • Keep diagrams maintainable. Editing the text updates the diagram, so there is no need to redraw manually.
  • Choose from many diagram types. Kroki! supports a range of textual diagram languages, which you can browse in the Diagram types section.
  • Learn quickly from examples. The Examples and Cheat sheet sections show working syntax you can adapt.

Who it is for

Audience Why it fits
Developers Embed diagram definitions alongside code and docs
Technical writers Produce consistent diagrams from text sources
Teams Store diagrams in version control and review changes as text

Getting started

  1. Open the Try section on kroki.io.
  2. Pick a diagram type from the Diagram types list.
  3. Write your diagram description in that language's syntax.
  4. Render it and adjust the text until the diagram looks right.
  5. Copy the working definition into your documentation or project.

If you are unsure of the syntax, check the Cheat sheet or the Examples for a starting point.

Key things to know

  • Kroki! is text-first: the diagram is only as good as the description you write.
  • The supported formats are listed on the site, so confirm your preferred language is included before committing to it.
  • The homepage describes the service as creating diagrams from textual descriptions, which is the main capability to rely on.