A complete guide to declarative diagramming with D2

Declarative diagramming, an approach that uses formal language to specify relationships and logic, facilitates the creation of complex diagrams like flowcharts and organization charts without the need for manual placement. D2 (D2lang) is a domain-specific scripting language that implements this approach, allowing engineers to generate diagrams from text using a simple syntax. Supported by the Terrastruct project, D2 enables users to customize diagrams extensively, including their appearance to match organizational branding, and supports various diagram types such as flowcharts and entity-relationship diagrams. Users can install D2 using different methods, including Go programming language or a CURL script, and can integrate it with popular applications through available plugins and extensions. D2's features, like styling and string handling, offer flexibility in diagram creation, making it a valuable tool for documentation and automating diagrams that evolve over time.