PwC · Primly Community

PwC senior / L5 system design interview, what to expect if you're coming from big tech

staff_steph · 3 replies

Interviewed for a senior SWE role at PwC's products and tech group last month. I'm coming from a cloud infrastructure background at a public tech company. Here's how the system design component played out, since the PwC system design interview experience is weirdly hard to find.

They do have a system design round. It's not the full 60-minute whiteboard you'd see at Amazon or Google, but it's real. Mine was embedded in the technical interview: about 30 minutes after a coding problem.

What they asked: Design a system that ingests audit data from multiple client sources, normalizes it, and surfaces anomalies to auditors in near-real-time. Very on-brand for PwC. It's not a generic "design Twitter" question. They leaned into their actual domain: financial services, audit, compliance, data pipelines.

What mattered: Being able to scope the problem and ask clarifying questions before diving in. I asked about data volumes and latency requirements upfront, which seemed to land well. High-level architecture: ingestion layer (Kafka was well received), some normalization service, storage (they seemed familiar with both relational and columnar stores), and an alert/dashboard layer. Trade-off discussion. Why Kafka vs. something simpler. Why not just batch-process. The interviewer pushed back a couple times and wanted to see reasoning, not just a diagram. Reliability and auditability of the system itself. Makes sense for an audit firm.

What didn't matter: Hyper-optimized capacity planning. I did rough napkin math on throughput and that was fine. Nobody pulled out a calculator.

If you're interviewing at senior level and coming from big tech: the system design bar is real but calibrated to professional services problems, not FAANG-scale. Strong communication about trade-offs matters more than getting to the "right" answer.

3 replies

sec_sasha

The audit data domain angle is interesting. Did they ask anything about security or access control for that pipeline? I'd imagine for PwC clients you'd need serious data segregation between clients.

sre_sol

They did mention it briefly. I brought up tenant isolation and they nodded but didn't go deep. Maybe a senior+ thing, or maybe they just ran out of time.

director_dee

PwC's systems group does some genuinely complex infrastructure work once you're past the consulting veneer. The system design calibration you described sounds about right for a senior IC hire. They're not grading on FAANG rubrics but they do want people who can architect client-facing platforms.