D2

D2 is a modern declarative diagramming language built around a simple idea: describe your diagram in text, and the tool renders it. The project positions itself as a fast way to move a mental model from your head onto the screen, with documentation, examples, a blog, and a playground available on the site.

The core features include a concise syntax and a set of production-ready themes created by professional designers, each with a distinct look. A sketch mode offers a hand-drawn aesthetic for a more informal feel. Diagrams can be edited and shared with a team, making iteration straightforward.

It is aimed at developers, technical writers, and teams producing documentation, wikis, and presentations who want diagrams that are easy to version and update. Because diagrams are defined in text, they fit naturally into docs-as-code workflows.

To get started, explore the documentation and try the playground to test syntax before committing to a larger diagram. The examples and blog posts show practical patterns. Overall, D2 is a solid choice when diagram source needs to live alongside text and change often.