Mermaid for
Class diagrams
Model your code before you write it
Design object models, define relationships, and document your architecture in a format that lives next to your code.
What is a class diagram?
A class diagram is a UML structural diagram that shows the classes in a system, their attributes and methods, and the relationships between them. The Object Management Group adopted UML (Unified Modeling Language) as a standard in 1997, and the class diagram is one of its most widely used diagrams.
Class diagrams are used for upfront design and for documenting existing codebases. In Mermaid, you write them as text with classDiagram. Mermaid supports inheritance, composition, aggregation, association, dependency, and realization; multiplicity labels such as 1 and 0..*; generics; visibility markers; annotations such as <<interface>>; and namespaces.
What you can map
with a
class diagram
Object-oriented system design
Domain model documentation
API resource structures
Inheritance and interface hierarchies
Database ORM layer design
Microservice data contracts
Framework and library architecture
Object-oriented system design
Domain model documentation
API resource structures
Inheritance and interface hierarchies
Database ORM layer design
Microservice data contracts
Framework and library architecture
Who uses class diagrams
on Mermaid
When a class diagram is
the right call
Less time syncing, more time building
One shared canvas for mapping ideas, collaborating live, and keeping teams on the same page, literally.
FAQ
Common questions about building class diagrams in Mermaid.
