What is Structurizr and how does it use the C4 model for software architecture diagrams?

Structurizr is a "models as code" tool for visualising, documenting, and exploring software architecture. You write Structurizr DSL to define a single model of your system, and from that one model it generates multiple software architecture diagrams following the C4 model. It was created by Simon Brown, the author of the C4 model, and remains the reference implementation — which makes it the strongest choice if C4 compliance and compatibility matter to you.

How the models-as-code approach works

Instead of drawing diagrams by hand, you describe your architecture as text. The model holds the elements (people, software systems, containers, components) and the relationships between them. Views then select what to show. Because every diagram is derived from the same model, the diagrams stay consistent with each other.

The Structurizr DSL example from the site shows this directly:

workspace {
    !identifiers hierarchical

    model {
        u = person "User"
        ss = softwareSystem "Software System" {
            wa = container "Web Application"
            db = container "Database Schema" {
                tags "Database"
            }
        }

        u -> ss "Uses"
        u -> ss.wa "Uses"
        ss.wa -> ss.db "Reads from and writes to"
    }

    views {
        systemContext ss "Diagram1" {
            include *
        }

        container ss "Diagram2" {
            include *
        }

        // styling...
    }
}

This single set of elements and relationships produces two diagrams. Add more views and you get more diagrams without redefining the underlying architecture.

The C4 diagram types Structurizr supports

Structurizr is specifically designed to support the C4 model for visualising software architecture. The diagram types listed on the site are:

• System Landscape diagram
• System Context diagram
• Container diagram
• Component diagram
• Dynamic diagram
• Deployment diagram

Diagrams are interactive (for example, zoom in and out), animatable, embeddable, and include an automatically generated diagram key/legend.

Why model-based consistency matters

When diagrams are drawn separately, they drift apart — a box renamed in one diagram keeps its old name in another. Structurizr avoids this by enforcing the C4 model rules against a single model. Every view is a projection of the same elements and relationships, so a change in the model propagates to all diagrams that include it.

This consistency is also what makes the tool AI-friendly. AI agents and LLMs excel at generating text, and Structurizr's model-based consistency and enforcement of C4 rules make it a good fit for teams generating C4 diagrams with AI. The text-based format is easy for agents to parse, enabling use cases such as AI summaries, queries, and detecting architectural drift. The Structurizr MCP server provides DSL validation, parsing, and inspection tools to assist with creating models.

Documenting and exploring beyond the standard diagrams

• Cloud architecture themes: prebuilt themes exist for Amazon Web Services, Microsoft Azure, Google Cloud Platform, Oracle Cloud Infrastructure, and Kubernetes, so you can document cloud architecture with recognisable icons.
• Alternative visualisations: tree views and interactive force-directed graphs let you explore the architecture from other angles.
• Supplementary documentation: you can publish documentation such as a "software guidebook" alongside the diagrams.

Where to start

1. Read the Structurizr DSL tutorial to learn the syntax.
2. Try it to write a small model and see the generated diagrams.
3. Define your own workspace: model your people, software systems, containers, and components, then add views for the diagram types you need.

If you want a single source of truth that produces consistent, interactive C4 diagrams — and you're comfortable describing architecture as code — Structurizr is built for exactly that. If your team prefers drawing tools over text, the models-as-code workflow will be the main adjustment.