EasyC4 diagram creator

Choose a format: PlantUML C4 ( @startuml … @enduml ) or Mermaid C4 ( C4Context , C4Container , or C4Component ).
Basics: ASCII double quotes; element ids use letters, digits, and underscores; every Rel must reference ids you already declared.
What to paste: the full diagram text in the editor - do not depend on !include or external files.
Details: use Examples for working samples and AI prompt instructions for the exact macro lists and rules.

Create C4 diagrams from PlantUML or Mermaid! Easily convert, open, and refine them in diagrams.net or draw.io - online! Free, easy-to-use C4 diagram tool - get beautiful diagrams in just seconds!

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Need an example?

The C4 model diagram samples for PlantUML and Mermaid. Pick a format and easy test how it works.

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