Zipline·Software Engineer·Onsite - System Design / Architecture
Jun 2026
System design round at Zipline for a software engineering role. The prompt was a railroad crossing control system, which sounds niche but actually covers a ton of ground: sensors, actuators, redundancy, failure modes. More depth required than I expected going in.
- Design a safe and redundant control system for an at-grade railroad crossing, covering train detection, road user warnings, gate control, failure handling, and maintenance support.
“This one is deceptively wide.” The rest of the author's notes on Software Engineer interview at Zipline, 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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