From Static to Dynamic: A Complete Guide to C4 Dynamic Diagrams for Visualizing Runtime Behavior with Visual Paradigm and PlantUML

Introduction

Software architecture documentation often faces a critical gap: we can beautifully map what a system is made of, but struggle to explain how it actually works when users interact with it. Static diagrams show structure—containers, components, and connections—but they leave readers wondering about the flow of data, the sequence of operations, and the runtime collaboration between elements.

Enter the C4 Dynamic Diagram. As one of the three supplementary diagrams in the C4 model (alongside System Landscape and Deployment diagrams), the Dynamic diagram bridges this gap by focusing on runtime behavior. It transforms abstract architecture into tangible narratives, showing how software systems, containers, or components collaborate over time to implement specific user stories, use cases, or business processes.

Whether you’re onboarding new team members, conducting architecture reviews, or documenting complex event-driven flows, Dynamic diagrams provide the clarity that static models alone cannot. This comprehensive guide walks you through everything you need to know: what C4 Dynamic Diagrams are, why they matter, when to use them, how to create them, and practical examples using both Visual Paradigm and C4-PlantUML.

1. What is the C4 Dynamic Diagram? Role and Purpose

The C4 Dynamic Diagram is one of the three supplementary diagrams in the C4 model (alongside System Landscape and Deployment diagrams). While the core C4 diagrams (Context, Container, Component, Code) are static structure diagrams, the Dynamic diagram focuses on runtime behavior.

• Role: It shows how elements from the static model (Software Systems, Containers, or Components) collaborate and interact over time to implement a specific user story, use case, feature, business process, or scenario.
• Purpose: To answer questions like:
  • How does the system actually work when a user performs a specific action?
  • What is the sequence or ordering of interactions between elements at runtime?
  • Where are the key integration points, synchronous/asynchronous calls, or event flows?

It is inspired by UML Communication Diagrams (numbered interactions with free-form layout) but can also be rendered in a more linear sequence-style format. This makes it excellent for explaining dynamic behavior without the full complexity of a pure UML Sequence Diagram.

2. Why Supplement the Core C4 Diagrams with a Dynamic Diagram?

The static C4 diagrams excel at showing what the architecture looks like (structure and relationships) but often leave readers wondering how it behaves at runtime.

Reasons to supplement:

• Static diagrams alone can feel abstract; dynamic diagrams make the architecture more concrete and easier to understand.
• They help identify risks in integration, performance bottlenecks, or failure points in specific flows.
• Great for onboarding new team members and explaining complex or asynchronous processes (e.g., event-driven architectures, message queues).
• Supports architecture reviews, threat modeling, and decision validation by focusing on real usage scenarios.

In short: Static diagrams show the map; Dynamic diagrams show how traffic actually moves on the roads for a particular journey.

3. When to Use the C4 Dynamic Diagram

Use it when:

• You need to explain how a specific feature or user story is implemented across containers or components.
• Documenting key business processes, login flows, order processing, payment handling, or event-driven flows.
• Onboarding developers or stakeholders who struggle to understand behavior from static diagrams.
• Analyzing or communicating asynchronous, event-based, or multi-step interactions.
• During architecture reviews or when evaluating design alternatives for a particular scenario.

It is optional and should be created selectively — only for important or complex flows. Avoid creating one for every possible use case.

[Image placeholder: Decision flowchart showing “When to create a Dynamic Diagram” with criteria like complexity, stakeholder needs, and risk assessment]

4. How to Create a C4 Dynamic Diagram

1. Choose scope — Pick one specific user story, use case, or feature (keep the scope narrow).
2. Select elements — Use elements from your existing static C4 diagrams (usually Containers or Components; sometimes Systems).
3. Define interactions — Number the steps (1, 2, 3…) to show ordering. Describe the interaction (e.g., “Submits order”, “Publishes event”).
4. Layout — Free-form (communication style) or more linear (sequence style). Add technology or protocol details if helpful.
5. Keep it focused — Do not try to show the entire system; one diagram = one scenario.

Always include a diagram key/legend and link back to the relevant static C4 diagrams.

[Image placeholder: Annotated screenshot showing the 5-step creation process with visual callouts]

5. How Visual Paradigm Supports C4 (Including the Dynamic Diagram and Supplementary Diagrams)

Visual Paradigm provides excellent first-class support for the full C4 model, including all six diagram types: System Context, Container, Component, System Landscape, Dynamic, and Deployment.

Key strengths (as of the December 2025 update and beyond):

• Dedicated C4 diagram types with correct notation, palettes, and styling for all levels, including Dynamic.
• AI-powered C4 diagram generation — Describe a user story or scenario in natural language, and it can generate a Dynamic diagram (plus the other views).
• Easy linking between diagrams (e.g., from a Container diagram drill-down to a Dynamic view for a specific flow).
• Support for both collaboration-style and sequence-style layouts.
• Collaboration features, templates, and integration with C4-PlantUML workflows.

This makes Visual Paradigm one of the most complete tools for end-to-end C4 modeling, especially when combining static structure with dynamic behavior and infrastructure views.

[Image placeholder: Visual Paradigm interface showing AI-generated C4 Dynamic Diagram with numbered interactions]

6. Key Concepts in the C4 Model (Relevant to Dynamic Diagrams)

• Hierarchical Abstractions: Software System → Container → Component → Code. Dynamic diagrams can operate at any of these levels but are most commonly used at Container or Component level.
• Static vs Dynamic: Static diagrams show structure; Dynamic diagrams show runtime collaboration for a scoped scenario.
• Supplementary Diagrams:
  • System Landscape — big-picture overview of multiple systems.
  • Dynamic — runtime behavior for a specific flow.
  • Deployment — mapping software to infrastructure.
• Focus on clarity and communication rather than formal rigor. Use numbered steps and concise descriptions.

7. Example Diagrams Using C4 PlantUML Code

C4-PlantUML is the most popular way to generate C4 diagrams as code. For Dynamic diagrams, include C4_Dynamic.puml.

Example 1: Dynamic Diagram – Online Banking “Make Payment” Flow (Collaboration Style)

@startuml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Dynamic.puml

‘ Optional: Horizontal layout often reads better for step-by-step flows
LAYOUT_LEFT_RIGHT()
LAYOUT_WITH_LEGEND()

title Dynamic Diagram: Make Payment – Online Banking

‘ 1. Define Elements
Container(customerMobileApp, “Mobile Banking App”, “Mobile App”, “Allows customers to manage accounts”)
Container(apiGateway, “API Gateway”, “Spring Cloud Gateway”, “Routes requests and handles auth”)
Container(paymentService, “Payment Service”, “Java Microservice”, “Processes payments”)
Container(notificationService, “Notification Service”, “Node.js Service”, “Sends email/SMS”)
System_Ext(paymentGateway, “External Payment Gateway”, “Third-party processor”)

‘ 2. Define Indexed Relationships
‘ Syntax: Rel(<from>, <to>, <label>, <technique>)
Rel(customerMobileApp, apiGateway, “1. Submits payment request”, “HTTPS/JSON”)
Rel(apiGateway, paymentService, “2. Forwards payment”, “Internal API”)
Rel(paymentService, paymentGateway, “3. Processes transaction”, “HTTPS”)
Rel(paymentService, notificationService, “4. Publishes PaymentCompleted event”, “Kafka / Async”)
Rel(notificationService, customerMobileApp, “5. Sends confirmation”, “Push Notification”)

@enduml

[Image placeholder: Rendered collaboration-style Dynamic diagram showing the payment flow with numbered arrows]

Example 2: Simpler Sequence-Style Dynamic Diagram (Login Flow)

@startuml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Sequence.puml

‘ Standard C4 styling for sequence diagrams
title Sequence Diagram: User Login Flow (Complete)

‘ 1. Define Participants
Person(user, “Bank Customer”, “Wants to access account”)
Container(webApp, “Online Banking Web App”, “React + Nginx”, “Customer UI”)
Container(authService, “Authentication Service”, “Spring Boot”, “Identity Provider”)
Container(userDatabase, “User Database”, “PostgreSQL”, “Credential Store”)

‘ 2. The Flow
‘ Syntax: Rel(from, to, label, technique)

Rel(user, webApp, “Enters credentials”, “HTTPS/Form”)

Rel(webApp, authService, “POST /api/v1/login”, “REST/JSON”)

Rel(authService, userDatabase, “SELECT user WHERE username=?”, “JDBC/SQL”)
‘ Showing the return message from the DB
Rel(userDatabase, authService, “Return hashed password & salt”, “SQL Result”)

Rel(authService, authService, “Verify Hash & Generate JWT”, “Internal Logic”)

Rel(webApp, authService, “200 OK (Return JWT)”, “JSON”)

Rel(webApp, user, “Redirect to Dashboard / Set Auth Cookie”, “UI Update”)

@enduml

Example 2: Dynamic Diagram

@startuml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Dynamic.puml

‘ Standard C4 Layout settings
LAYOUT_WITH_LEGEND()
‘ Left-to-right layout is often better for step-by-step dynamic flows
LAYOUT_LEFT_RIGHT()

title Dynamic Diagram: User Login Flow

‘ 1. Define Elements
Person(user, “Bank Customer”, “Wants to access account”)
Container(webApp, “Online Banking Web App”, “React + Nginx”, “Provides UI for customer login”)
Container(authService, “Authentication Service”, “Spring Boot”, “Handles identity and token generation”)
Container(userDatabase, “User Database”, “PostgreSQL”, “Stores hashed credentials and profile data”)

‘ 2. Define Dynamic Interactions
‘ Note: Numbering is included manually in the label for clarity
Rel(user, webApp, “1. Enters credentials”, “HTTPS”)
Rel(webApp, authService, “2. Authenticates”, “REST/JSON”)
Rel(authService, userDatabase, “3. Validates credentials”, “JDBC/SQL”)
Rel(authService, webApp, “4. Returns JWT token”, “JSON”)
Rel(webApp, user, “5. Grants access to dashboard”, “UI Update”)

@enduml

You can find more official samples (including message bus and Big Bank PLC examples) in the C4-PlantUML GitHub repository under the samples folder.

Final Tips for Your Article

• Stress that Dynamic diagrams complement (but do not replace) UML Sequence Diagrams — they stay at the C4 abstraction level and are usually simpler.
• Recommend creating Dynamic diagrams only for the most important or risky scenarios.
• Include side-by-side visuals: a static Container/Component diagram next to its corresponding Dynamic view.
• Highlight how tools like Visual Paradigm (with AI support) and C4-PlantUML make it fast to iterate from static to dynamic views.

Conclusion

C4 Dynamic Diagrams are a powerful yet underutilized tool in the software architect’s toolkit. By shifting focus from structure to behavior, they transform abstract architecture into actionable narratives that stakeholders can understand, developers can implement, and teams can validate.

Remember: Dynamic diagrams are optional and should be used selectively. Create them for complex, high-risk, or frequently misunderstood flows—not for every feature. When paired with static C4 diagrams, they provide a complete picture: the map and the journey.

Whether you choose Visual Paradigm’s AI-powered generation for rapid prototyping or C4-PlantUML for code-based precision, the goal remains the same: communicate architecture clearly, reduce ambiguity, and align teams around how the system actually works. Start small, focus on one critical user story, and let your Dynamic diagram bring your architecture to life.

References

1. Dynamic diagram | C4 model: Official documentation explaining the purpose, scope, and usage guidelines for C4 Dynamic Diagrams, including collaboration and sequence style examples.
2. AI C4 Model Generator – Visual Paradigm Product Updates: Announcement detailing Visual Paradigm’s AI-powered generation of all six C4 diagram types, including Dynamic diagrams, from natural language descriptions.
3. C4 Diagram Tool & Modeling Software – Visual Paradigm: Overview of Visual Paradigm’s dedicated C4 modeling capabilities, featuring support for Dynamic diagrams alongside Context, Container, Component, Landscape, and Deployment views.
4. C4-PlantUML/samples/C4CoreDiagrams.md at master – GitHub: Collection of official C4-PlantUML sample diagrams, including Dynamic Diagram examples reproducing Simon Brown’s reference models.

5. Mastering C4 Diagrams in Visual Paradigm: A Hands-On Review: Practical review comparing Visual Paradigm’s four methods for creating C4 diagrams, with specific coverage of Dynamic diagram workflows.