Build a Resilient Bootstrap API with Partial Upstream Results

Implement the design of a resilient bootstrap API that accepts user_id and combines information from three existing upstream services. Boilerplate and mock services are available.

Requirements and Constraints

• Consumer accepts user_id and returns user information including consumer_id and roles.
• Payment accepts consumer_id and returns the default card and available gift-card credit.
• Address accepts consumer_id and returns the formatted address, first name, and last name.
• user_id and consumer_id are different identifiers.
• Consumer failure may make the bootstrap request fail with HTTP 500.
• Payment or Address failure must preserve the remaining available information.
• The result must include the required address name fields when Address succeeds.

Explain the call sequence, response structure, HTTP and timeout handling, and the tests needed to demonstrate the required behavior. This is a service-integration exercise; no real upstream endpoint or response schema beyond the listed fields is supplied.

Clarifying Questions

• Which non-success status codes can each upstream return, and which ones mean the upstream data is absent rather than temporarily unavailable?
• How should the bootstrap response represent an unavailable optional section: omission, null, or a structured error?
• What total request deadline and per-upstream timeouts are acceptable?
• Are the upstream operations safe to retry, and would retrying fit within the caller's remaining deadline?