C4 Model

C4 model diagrams

Generate C4 model diagrams with AI. System Context, Container, Component, and Code views — in Mermaid C4 or PlantUML C4 syntax.

The four levels of C4

L1

System Context

Big picture. Your system as a box, showing users and external systems it interacts with. For stakeholders and new team members.

L2

Container

Zoom in. Applications, services, databases, and message brokers. How the system is deployed and what tech stack is used.

L3

Component

Inside a container. Major modules, packages, and their relationships. For developers working on a specific service.

L4

Code

Class-level detail. UML class diagrams or entity-relationship diagrams. For detailed design of a specific component.

C4 in Mermaid syntax

C4Context
  title System Context — E-Commerce Platform

  Person(customer, "Customer", "Browses and buys products")
  System(ecommerce, "E-Commerce Platform", "Handles orders, payments, inventory")
  System_Ext(payment, "Payment Gateway", "Processes credit card payments")
  System_Ext(shipping, "Shipping Provider", "Delivers orders")

  Rel(customer, ecommerce, "Places orders")
  Rel(ecommerce, payment, "Sends payment requests")
  Rel(ecommerce, shipping, "Creates shipments")

Paste this into Cybewave or let AI generate it from a description.

C4 container diagram in Mermaid

C4Container
  title Container Diagram — E-Commerce Platform

  Person(customer, "Customer", "Browses and buys products")

  System_Boundary(ecom, "E-Commerce Platform") {
    Container(webapp, "Web App", "React", "Product catalog and checkout UI")
    Container(api, "API Server", "Node.js/Express", "REST API and business logic")
    ContainerDb(db, "Database", "PostgreSQL", "Users, orders, products")
    ContainerDb(cache, "Cache", "Redis", "Sessions and product cache")
  }

  System_Ext(stripe, "Stripe", "Payment processing")

  Rel(customer, webapp, "Browses", "HTTPS")
  Rel(webapp, api, "API calls", "HTTPS/JSON")
  Rel(api, db, "Reads/writes", "SQL")
  Rel(api, cache, "Caches", "Redis")
  Rel(api, stripe, "Pays via", "HTTPS")

Level 2 zooms inside the system boundary to show applications, databases, and their protocols.

When to adopt C4 model diagrams

C4's layered approach shines in these real-world scenarios.

🏢

Large-scale system documentation

When your platform spans dozens of services across multiple teams, C4 provides a structured way to document everything from the 10,000-foot view down to individual component interactions.

🎯

Cross-audience architecture communication

Executives want the context diagram, architects need the container view, and developers drill into components. C4 gives each audience the right level of detail without maintaining separate documents.

🔍

Zoomable context-to-code navigation

Start at system boundaries and progressively zoom into containers, components, and code. Each level answers different questions—from “what systems exist?” to “how is this service structured?”

🏛️

Multi-team architecture governance

When multiple squads own different services, C4 container and component diagrams clarify ownership boundaries, API contracts, and shared infrastructure dependencies.

🎤

Architecture interview presentations

System design interviews reward structured thinking. C4's four levels map naturally to interview flow—start broad with context, then zoom in to show depth and technical decision-making.

📋

Enterprise client deliverables

Consulting firms and agencies use C4 diagrams in architecture proposals and technical assessments. The standardized notation communicates professionalism and thoroughness to enterprise buyers.

Why the C4 approach matters

Most architecture diagrams fail because they try to show everything at once. A single diagram with fifty services, their databases, message queues, and external integrations becomes an unreadable wall of boxes and arrows. C4's four-level hierarchy solves this by matching diagram detail to audience need—executives see system context, platform engineers see containers, and service owners see components.

This layered approach also scales with your organization. A startup with three services needs one context diagram and a few container views. An enterprise with two hundred microservices uses the same framework, adding component diagrams per team and code-level views for critical paths. The notation stays consistent whether you have five engineers or five hundred.

AI-powered C4 generation accelerates adoption dramatically. Instead of learning Structurizr DSL or crafting Mermaid C4 syntax by hand, describe your system and get all four levels generated. The AI understands C4 conventions—external systems get dashed borders, containers include technology labels, and relationships show data flow direction. You refine the output rather than building from a blank canvas.

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