DoorDash Code Craft Round Midlevel SWE Onsite Interview Experience USA

Context and Format The interview consisted of a collaborative, practical coding exercise rather than a standard algorithmic problem. The scenario involved migrating from a monolith to a microservi

Context and Format The interview consisted of a collaborative, practical coding exercise rather than a standard algorithmic problem. The scenario involved migrating from a monolith to a microservice architecture, specifically tasking the candidate with building a new Payments Service to handle Dasher payouts.

Problem Statement The goal was to create an API with a POST /payout endpoint. *

Input: dasherId *

Output: The calculated dollar amount for the Dasher. *

Dependencies: The service required logic to request delivery activity data from an upstream source. For the exercise, this external data was mocked via a helper function.

Calculation Logic The payment model was time-based with the following specific rules: *

Base Rate: $0.30 per minute. *

Concurrency Multiplier: If a Dasher handles multiple orders simultaneously, the pay rate scales based on the number of ongoing deliveries (e.g., Rate = Count of Active Orders × $0.30). *

Requirements: The solution required a working implementation of this logic along with comprehensive test coverage.

Solution and Discussion The implementation process involved defining a data structure for the mock activity data and writing the algorithm to parse sequential order activities. Once the core logic was functional and tested, the remainder of the session focused on systems thinking and robustness. Key discussion points included: 1.

Edge Case Handling: Identifying specific scenarios where the logic might fail and refactoring the code to handle them. 2.

System Reliability: Analyzing how the service should behave if the upstream data dependency experienced high latency.