The scenario
Build a startup response from account, payment, and address services. Repair a dependent lookup, keep useful data during a partial outage, and bound retries. This original practice is informed by DoorDash community reports.
A failure to reason about
A payment service returns an error even though its response still contains card details. The address service succeeds. Decide which information the client can safely receive and which calls should be retried.
Illustrative context for the topic. The exercise’s full requirements arrive in the workspace.
Questions to bring to your review
- Which identity does each downstream service expect?
- Which failures prevent dependent calls?
- How do response statuses differ from payload presence?
- When should an individual service stop retrying?
Skills you will practice
- API composition
- Identity boundaries
- Partial failure handling
- Retry policy
- Regression testing
Read the existing code, reproduce the reported behavior, review proposed changes, and verify your final implementation. You can use AI assistance while staying responsible for the result.
Prepare with a worked example
- How to review AI-generated code in an interview
Work through a flawed AI patch, design a regression that exposes it, and explain a repair with evidence. A practical code-review exercise for AI-assisted interviews.
See how nrml evaluates an attempt, including the limits of automated evidence.