Build a Courier Payout Service System Design Interview

1. Problem Statement

2. Architecture Discussion Map

Use this as one discussion aid, not a single correct answer. Your design should follow from the requirements, scale, and trade-offs you establish.

graph LR
    A["Build a Courier Payout Service"]
    A --> F1["Payout API and rule modeling"]
    A --> F2["Idempotency and duplicate requests"]
    A --> F3["Upstream latency and retries"]
    A --> F4["Money precision and audit history"]
    A --> F5["Testing changing compensation rules"]

3. Key Focus Areas

• 1
  Payout API and rule modeling
• 2
  Idempotency and duplicate requests
• 3
  Upstream latency and retries
• 4
  Money precision and audit history
• 5
  Testing changing compensation rules

4. What Strong Candidates Should Demonstrate

• ✓Turn compensation rules into deterministic, testable calculations.
• ✓Make payout creation idempotent and auditable.
• ✓Handle slow or unavailable upstream order services.