Architecture Mapping tool

C4 Model

Communicates software architecture through context, container, component and code diagrams at useful levels of detail.

Core question

Which diagrams let each audience understand the software architecture?

Plan C4 Model Method guide

Start comparison

Give feedbackIs this method useful to you?

Participants: 1-5
Time: 1-4 h

The steps are a practical sequence; adapt them to the method’s purpose and available evidence.

A paper-based illustration representing C4 Model with its core stages and visible working result.

Question
Choose system, audience and question
Define one system-of-interest boundary and the understanding question the diagrams must answer.
Context
Draw system context
Show the system as one box with people and external systems; label relationships by purpose and interaction.
Containers
Add container view
Decompose the system into applications, services and data stores; name responsibility and technology when useful.
Detail
Maintain only useful zoom levels
Add component, code, dynamic or deployment diagrams only to resolve a question; label legend and ownership.

Revisit the model when evidence, context or outcomes change. Record what changed and why.

A good fit when

Use it when: Architecture Communication, Onboarding. The group can provide the evidence and authority the method requires.

Ideal for

Architecture communication
Onboarding
Design reviews

Not good for

Domain discovery
Strategic market analysis

Outputs

C4 diagram set
System context, containers and further zoom levels when they serve a clear purpose.
Coherent set of C4 views
The artifact records scope, date, participants, source version, and owner, including changed assumptions and the reason for each revision.

C4 views

Fictional worked example

Fictional context diagram for a practice portal: patient uses web app; practice staff use admin interface; portal queries practice management and sends confirmations through email service. Container view below: web frontend, booking API, appointment database. Label the relationship: API reads open slots and requests reservation. No component view unless it answers a concrete question.

System context

Show the system, people and neighbours with relationships.

Patient → practice portal → practice management.

Container

Show applications, services and data stores inside the boundary.

Web app → booking API → appointment database.

Component

Decompose internal components only to resolve a question.

Booking service checks availability and reservation.

Code

Use code level only when detail is useful.

No code diagram without a concrete reader need.

Supporting diagrams

Add dynamic, deployment or landscape when the communication needs it.

Deployment view for operations handover.

The example text is fictional; replace it with sourced project information.

C4 model: Diagrams

First step

Define one system-of-interest boundary and the understanding question the diagrams must answer.

Open the method guide

Good to do first

Architecture

arc42

Supplies the system context that the C4 views then refine step by step.

Where to go next?

Paper illustration of two considered options leading to a decision record with a marked status and visible consequences.

Architecture

Architecture Decision Record

Documents why a container or component boundary was drawn that way.

Domain Modeling

Context Map

Zooms out from the system view into the business bounded contexts behind it.

Deep dive

Purpose

The C4 Model makes a system legible across several resolution levels, from context down to code. It suits situations where different audiences need to understand the same architecture from different altitudes.

How it works

First the system context is described with people, neighboring systems, and boundaries. Then containers, components, and, if needed, a code view are added as supplements. This keeps the architecture connectable at every level without overloading a single diagram.

In detail

The C4 Model works because it shows the same architecture at graduated resolutions, reaching different audiences without diagram overload. Good use keeps the abstraction disciplined at each level and avoids mixing context, container, and detail in one picture. The approach becomes effective when relationships, responsibilities, and interfaces are clear enough per view that understanding questions get resolved faster and wrong assumptions are caught earlier.

Facilitation

Clarify beforehand which view is needed for which conversation so you don't draw everything at once out of habit. A key moment happens where one level no longer suffices and the group deliberately moves to the next. Close with a compact set of maintained views and clear rules on when each one needs updating.

The method guide walks execution through 4 phases, timing, 4 pitfalls, and clear stop criteria.

Open method guide

Your perspective

Does this method help with your work?

Your feedback helps shape the next improvements to methodatlas.

Sources and topics

Topics

Architecture Communication Visualization

Sources

C4 model: Diagramsc4model.comc4model.com by Simon Brown; describes the four abstraction levels Context, Container, Component and Code.

In playbooks

Build Architecture DocumentationMove from scattered architecture knowledge to views, decisions, and communicable documentation.

Artifact templates

C4 Model: WorksheetPrepare the decision, source evidence and next review.

markdown

c4-model-working-template.md

Prepare the decision, source evidence and next review.

C4 Model: Worksheet

Question

To be confirmed

Desired outcome

To be confirmed

Scope

Run the method Time: See catalog planning range; no universal duration.

Complete this worksheet on paper or in your own document during the work.

Preparation for this scope

Method setup

Materials: Shared visual workspace, source evidence, and an agreed decision question.
Roles: Architect or lead developer, developers, product/domain representative.
Advance information: Collect existing data, examples, constraints and relevant stakeholder perspectives.
Overall time needed: 60–120 min for an initial model; detail and review depend on system scope.
Setup: Name software system, boundary, audience and question the diagram must answer. Show users and neighboring software systems with named relationships. Decompose the chosen system into applications/data stores/containers and technologies. Zoom into components or code only when the audience needs that level. Check consistent scope, relationship labels, legends and diagram owner.