Step 4: Technical Components and APIs

Outline the technical structure of your system.

1. Identify the components in your system that support the actions and flows defined earlier. Expand them to cover precisely the boundaries that the technical component should have.

2. Do the same with external systems. Since you don’t know the structure of the external system, simplify them as one box.

3. Name the interfaces between all the components and external systems. These are your APIs. Optionally, use a different notation for Asynchronous (dashed lines) and Synchronous APIs (solid lines).

4. Ensure the actions and technical lanes make sense together and that anybody can understand how the sequence of actions maps to components and APIs.

MoSy Core Diagram: Components and APIs (grey)

Combines well with:

• C4 model - container diagram

  • You can use it as a source or produce it from the MoSy board.
  • You can combine all flows to compose an aggregated view of the components in your system or use different diagrams.
  • Suitable for technical audiences. Simple to draw on a whiteboard.

• UML Sequence diagram

  • It’s a different view, with components and actors in columns.
  • Suitable for technical audiences. Simple to draw on a whiteboard.