A simple system for scheduling trainings evolves, leading to API endpoints for confirming trainings and booking resources.
When a new requirement for scheduling meetups arises, the team duplicates the training planner service, creating technical debt.
A new business rule for room cancellation fees reveals a deeper architectural problem about where financial logic should reside.
Proposed solutions, like one service calling another's API for data, demonstrate the anti-pattern of crossing service boundaries for decision-making.
Different team perspectives show that seemingly small technical choices, like reusing an endpoint, are actually critical strategic business decisions.
To avoid flawed designs, ask which bounded context owns a decision, who bears the long-term cost, and if the API increases team autonomy.
The system is reframed using capability layers (like resource booking) and operations layers (like training planning) to prevent domain logic from leaking.
An AI twin helps formally define the purpose, language, and communication patterns for the Training Planner and Resource Booking bounded contexts.
By imagining future use cases like booking desks or concert tickets, you can test the architecture's stability and avoid coupling to current requirements.
A 2x2 matrix helps decide whether to implement, design for, or ignore potential features based on their likelihood and future implementation cost.
Instead of making large, slow decisions, focus on stabilizing small parts of the architecture to unblock teams and maintain momentum.
The relationship between services is changed to an open host service model, supported by a team structure of platform and stream-aligned teams.
The cancellation fee problem is solved by identifying a new bounded context, 'Event Economics', which correctly owns the financial decision-making logic.
Effective architecture isn't about applying the entire DDD framework, but about using the minimal required concept at the precise moment it's needed.
Jobs that call for the skills explored in this talk.