Aggregate Internal Services with Critical and Optional Dependencies

Build a backend endpoint that calls multiple internal services and aggregates their data into one response. Some dependencies are critical; if a noncritical service fails, return a useful partial response. Use clear strongly typed models and make the code testable. Discuss retries, jittered backoff, and circuit breakers. ### Clarifying Questions Identify which fields require each dependency, which failures prevent a valid response, and the overall deadline. The concrete services and schema are unspecified. For a worked example, choose a required profile service and an optional recommendations service, labeling these as practice choices. ### What a Strong Answer Covers Typed dependency interfaces, bounded concurrent calls, deadline propagation, explicit partial-result metadata, retry classification, circuit behavior, and tests with controlled dependency outcomes. ### Follow-up Questions - Why is an empty recommendation list different from an unavailable recommendations service? - How can retries make an overloaded service less available?