Engineering / Free editable template

C4 context diagram template

A C4 system context diagram is the zoomed-out first level of the C4 model: one box for your system, the people who use it and the systems it depends on. This example for a project tracking product shows three user roles, five external systems and labelled arrows saying what passes between them.

Use this template →See the example ↓

No account needed · Opens as your own editable page

Preview the c4 context diagram

View full-size preview ↗
C4 context diagram example showing people with roles and descriptions, the system in scope and its external systems, labelled relationships with protocols, plus a key
Everything in this example is editable. Replace the labels, move the shapes and adapt the layout to your work.

How to use this template

  1. List the people first

    Write down every type of user, including internal staff such as support agents. Roles matter more than job titles, because they explain why someone uses the system.

  2. Add only direct dependencies

    Include the external systems your product talks to directly, such as identity, billing and email. Leave out internal services: they belong on the next level down, the container diagram.

  3. Label every arrow

    Describe what each relationship does in plain words, then add the protocol in brackets. An unlabelled arrow forces readers to guess, which defeats the point of a context diagram.

Questions about this template

Can I zoom in from this to a C4 container diagram?

Yes. Duplicate the page and replace the system in scope with its apps, databases and services, keeping the people and external systems at the edges.

Do I need an account to use it?

No. Open the template and edit it in your browser. Your work saves on this device. An account is optional if you want to sync your workspace.

Can I export the finished diagram?

Yes. Use Export in the editor to save a PNG, SVG or PDF, or download an editable .epicdraw backup.

More Engineering templates →