went through the Starbucks tech loop last spring for a senior SWE role (they call it L5 internally, though they don't publicize leveling much). sharing notes because i couldn't find good info before going in.
the system design round was 60 minutes with two engineers. no LeetCode-style coding, just the design discussion. they gave me a prompt along the lines of: design the ordering and loyalty points system for a high-traffic mobile app. very on-brand for them obviously, but actually a solid prompt because it touches a lot of interesting problems.
what they were probing: how you handle concurrent writes (think: two tabs trying to redeem the same points) scalability of the menu catalog across thousands of locations with regional variations API design between the mobile client and backend caching strategy, especially for read-heavy things like menu display vs write-heavy things like order submission failure modes and retry behavior
they were NOT looking for a perfect answer. one interviewer explicitly said early on: "we care more about how you think through tradeoffs than arriving at a specific design." i took that seriously and kept narrating my reasoning out loud.
the second engineer asked almost no questions for 30 minutes then lit up when i started talking about queue-based order processing and dead letter queues. lesson: bring up async processing, it resonated.
one gotcha: they asked about multi-region. i had not prepared for that specifically. didn't tank the loop but it caught me off guard. if you're going into this: know your CAP theorem basics and be ready to talk eventual consistency in the context of loyalty points specifically.
overall design difficulty: solid mid-level FAANG system design bar, not Google-hard. if you've prepped the standard distributed systems topics you'll be fine. the coffee context is a gift because you can be super concrete about real user scenarios.
took about 12 days from the design round to receiving an offer. happy to answer specifics.