DoorDash·Software Engineer·Technical Phone Screen
May 2026
DoorDash system design round for a software engineer role, focused on extending an existing pay calculation system. Two parts: adding peak-hour bonus logic, then handling bad input. Pretty involved for a single session.
- You have a Dasher pay calculator. Extend it to apply a peak-hour bonus when a delivery falls within a configured time window. How do you handle multiple overlapping windows, and what rule governs which bonus applies?
- How would you handle invalid or malformed input in the pay calculator? Think missing fields, bad timestamps, negative values, and currency mismatches. What's your policy: reject, fall back, or compute partial pay?
“I went with highest-bonus wins and documented it as the policy, which felt cleaner than first-match since first-match is basically arbitrary depending on list order.” The rest of the author's notes on Software Engineer interview at DoorDash, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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