Mermaid C4 Architecture Diagram Tool

Express software system architecture based on the C4 model, showing system design step by step from context and containers to component levels.

What is a C4 diagram

A C4 diagram is a modeling approach for software architecture visualization. It shows system structure at different levels such as context, containers, components and code. C4 architecture diagrams help development teams and architects understand system boundaries, module relationships and technical architecture at different granularities. They are a common tool in modern software architecture design.

Use cases

Software architecture design

Show software system structure at different levels, helping teams understand system composition and dependency relationships.

System context analysis

Show the relationships between the system, users and external systems, clarifying system boundaries and responsibilities.

Container architecture design

Describe the deployment relationships between technical components such as application services, databases and message queues.

Component relationship analysis

Further break down internal system modules to show interactions and dependencies between components.

Technical solution review

Used for architecture review, technical communication and project documentation, improving the team's understanding of system design.

C4 diagramFree templates

E-commerce System Context

E-commerce System Context

Payment Service Component Diagram

Payment Service Component Diagram

How to generate a C4 diagram

1

Multiple editing methods

You can generate C4 diagrams by writing Mermaid code, AI generation, image recognition, code summary and more. You can also draw C4 architecture diagrams using our built-in C4 diagram templates.

2

Auto rendering

After entering Mermaid syntax, C4 diagrams are generated and previewed in real time, with support for custom C4 diagram styles and themes.

3

Export or share

You can download C4 diagrams and save them locally. We support exporting C4 diagrams to PNG, PDF, SVG, JPG, Markdown and other formats, or clicking the “Share” button to share the link with others.

4

Edit again

If you are not satisfied with the result, click the “Visual editing” button to edit the C4 diagram again in the ProcessOn editor.

C4 diagramCommon syntax

Syntax
Graphic
Meaning
C4Context
System context diagram
Create a C4 system context diagram
C4Container
Container diagram
Create a C4 container diagram
C4Component
Component diagram
Create a C4 component diagram
C4Dynamic
Dynamic interaction diagram
Create a C4 dynamic interaction diagram
C4Deployment
Deployment diagram
Create a C4 deployment diagram
title
Title
Set the C4 diagram title
Person(alias, "label", "description")
Person
Represents a user or role that uses the system
Person_Ext(alias, "label", "description")
External person
Represents people or organizational roles outside the system that participate in interactions
System(alias, "label", "description")
System node
Represents the software system to be analyzed
System_Ext(alias, "label", "description")
External system node
Represents third-party services or external software systems the system depends on
System_Boundary(alias, "label")
System boundary
Represents the system scope boundary
Container(alias,"label","technology")
Container
Represents an independently runnable software unit inside the system
ContainerDb(alias,"label","technology")
Database
Represents the data storage component in the system
Container_Boundary(alias, "label")
Container boundary
Represents the scope of a container or service
Component(alias,"label","technology")
Component
Represents a software module with clear responsibilities inside a container
ComponentDb(alias,"label","technology")
Data component
Represents the data access or data storage module used inside a component
Component_Boundary(alias, "label")
Component boundary
Represents the scope of a component set
Deployment_Node(alias,"label","technology")
Deployment node
Represents the infrastructure environment where the software actually runs
Container_Instance(alias,"label")
Container instance
Represents the software instance actually running in the deployment environment
Rel(source,target,"label")
Relationship
Define the call, interaction or data passing relationship between two elements
BiRel(source,target,"label")
Bidirectional relationship
Represents bidirectional communication or data exchange between two elements
Rel_Back(source,target,"label")
Reverse relationship
Represents a relationship from the target node back to the source node
Rel_Back_Neighbor(source,target,"label")
Neighboring reverse relationship
Represents a reverse connection between adjacent nodes
More Syntax

Why choose us

Online editing tool

Free templates

Powerful AI capabilities

Real-time preview

Export in multiple formats

Supports re-editing

C4 diagramDrawing questions

What is a Mermaid C4 diagram?

A Mermaid C4 diagram is a software architecture diagram based on the C4 model, used to describe system structure at different levels including system context, containers and components.

Are Mermaid C4 diagrams suitable for software architecture design?

Yes. Mermaid C4 diagrams help architects and development teams clearly express system boundaries, service composition and relationships between modules.

What levels do Mermaid C4 diagrams include?

Mermaid C4 diagrams usually include context diagrams, container diagrams, component diagrams and code-level structure diagrams. Different levels show software architecture information at different granularities.

What is the difference between Mermaid C4 diagrams and regular architecture diagrams?

Mermaid architecture diagrams usually focus on system module relationships, while Mermaid C4 diagrams are based on a standardized modeling approach that helps teams understand complex software systems from a hierarchical perspective.

How to create a Mermaid C4 diagram?

Users can define systems, containers, components and relationships with Mermaid C4 syntax to quickly generate software architecture diagrams that comply with the C4 model.