Design a rider onboarding application

Problem

Design a rider onboarding application end to end.

Areas covered

• Requirements scoping for the onboarding flow
• SQL vs NoSQL choice (heavily probed)
• DynamoDB internals: index types, partition keys, sort keys
• Reducing HTTP latency: status-code-based retries, long polling, short polling

Discussion points

• Data model and storage choice, with justification
• API design and the latency/retry strategy
• Trade-offs under scale