Did the senior/L5 equivalent loop at PepsiCo last month. The system design round caught me a little off guard because I expected a standard "design Twitter" type prompt and got something much more domain-specific.
Prompt I got: design a real-time inventory visibility system for a retail distribution network. Lots of stores, lots of SKUs, you need freshness + consistency + cost tradeoffs.
I'm sharing this because it's a useful pattern: PepsiCo's system design questions are often grounded in their actual business. CPG supply chain, retail data flows, demand forecasting pipelines. If you've only prepped pure web-scale problems like URL shorteners and ride-sharing dispatchers, you might feel disoriented.
What they cared about: Trade-offs. They pushed hard on why I chose eventual consistency over strong consistency in one part of the design. Wanted to hear me reason it out, not just pick an answer. Scalability vocabulary. Partitioning strategies, cache invalidation, pub/sub vs polling. Didn't need to go super deep on any single thing, but needed to show I could talk across layers. Failure modes. What breaks under load, what degrades gracefully, how does the system behave during a network partition. Classic SRE-flavored questions but applied to the domain. Cost awareness. This surprised me. They asked what the cost implications of my storage choice were and whether I'd considered cheaper options for cold data. Very enterprise-brained.
What they didn't push on: Microbenchmarks, specific cloud provider services (they asked it provider-agnostic), exact numbers for QPS calculations. They wanted reasoning, not memorized formulas.
The interviewer was a staff-level eng. Good questions, no ego. Felt like a real technical conversation, not a gotcha gauntlet.
Total round: 50 minutes. About 10 minutes of clarifying questions, 25 minutes of design and diagrams on the virtual whiteboard, 15 minutes of deep-dive into two components I chose. Time management matters here, don't let the clarification phase run long.