Google·Software Engineer·Onsite - System Design / Architecture
Jun 2026
Staff-level onsite at Google for SWE, two back-to-back system design rounds plus a behavioral round. The bar is noticeably higher than senior: interviewers are explicitly comparing you against that level and the differentiator is decision depth, not how fancy your architecture looks.
- Design a distributed rate limiter as an internal service supporting 100k+ QPS, multiple tenants, and multiple regions.
- Design a global real-time notification system handling push, email, and SMS for 100 million+ users, including fan-out, retry logic, and deduplication.
- Design an anomaly detection system. The domain is intentionally unspecified: you need to clarify whether this is metric streams, user behavior, or infrastructure alerts before proceeding.
- Design a Find My Device system (similar to Find My iPhone), with explicit attention to privacy, security, and efficiency constraints.
- Design a global menu update system for a chain restaurant, covering multi-region sync, offline-tolerant edge devices, and time-of-day menu variants.
- Design a dictionary range query store: store a set of words and support a range query returning all words in a given lexicographic interval. Discuss trie structures, sorted indexes, and sharding approaches.
- Walk through how your system handles failure scenarios: what happens when a region disconnects, when storage fails, or when a tenant abuses the system? Make concrete fail-open vs fail-close decisions.
- Describe the evolution path for your design: how does it scale from an MVP to 10x and then 100x load? Where would you re-architect and how would you roll out the new design?
“The failure mode I kept seeing in prep (and honestly did myself the first few mocks) is jumping straight to 'token bucket on Redis' without asking who the tenants are or what the latency SLO is.” The rest of the author's notes on Software Engineer interview at Google, Onsite - System Design / Architecture round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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