Went through the DoorDash senior SWE loop in April 2026, targeting L5. Two system design rounds total: one in the technical screen and one during the virtual onsite. Wanted to give actual signal, not vibes.
Technical screen system design: 45 minutes. Prompted with something in the delivery/logistics domain. Mine was around designing a real-time driver location tracking system. They care a lot about scale thinking early: how many drivers, how many requests per second, where do you store location state. The interviewer wasn't reading from a rubric but kept nudging toward tradeoffs. Bring up consistency vs latency explicitly; don't wait for them to ask.
Onsite system design (round 2): Harder. More open-ended. I got a prompt roughly around "design a restaurant search and ranking service." The trick there is that DoorDash is a marketplace, so the right framing is: you're optimizing for both restaurant supply and consumer demand simultaneously. They liked when I brought up how ranking might differ for a first-time user vs a repeat user, and how you handle restaurants in different fulfillment states (busy, closed, no drivers nearby).
Interviewer was pretty senior, asked a lot about capacity estimation and then pivoted hard to database schema and API contracts. Be ready to go deep on both. You can't just sketch boxes.
Leveling signals they seemed to care about: Scope, communication, handling ambiguity up front instead of charging into a design. Also: do you know when to stop designing and start prioritizing? I had a moment where I tried to cover too much and they basically said "ok, what would you ship first?"
Prep that helped: Designing distributed systems around geospatial data (S2/geohashing), event streaming (Kafka-style at scale), and read-heavy vs write-heavy storage tradeoffs. DoorDash has a public engineering blog with a few solid system architecture posts; worth reading before your loop. They reference internal infrastructure in ways that hint at what matters.
Total loop: phone screen (45 min coding + brief design), then onsite was 4 rounds: coding, system design, behavioral, cross-functional. Verdict was about 10 days after onsite. TC offer thread separate.