Tell me about a time when you had a significant technical disagreement with senior engineers or stakeholders about an architectural decision.
Behavioral rounds at FAANG and AI labs now include 1-2 design follow-ups. Each answer below ships with both.
The situation, your role, and the stakes, compressed.
I was tech lead on a zero-shot time-series forecasting API at a previous large tech company. The infrastructure team wanted strict model versioning and rollback up front (3-4 weeks of work); a partner product team needed the API live in 2 weeks for capacity forecasting. As lead, I owned the trade-off, and the API was a foundational service planned to serve hundreds of daily requests, so neither side was wrong on principle.
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Design Follow-Ups
The new behavioral roundBehavioral rounds increasingly drop into 1-2 technical follow-ups that probe whether you could actually build the system you described. These are the design questions a real interviewer would ask after this STAR answer.
Walk me through the API contract you'd actually ship. What's the request/response shape for `/v1/forecast` vs `/v2/forecast`, and how do clients migrate without breaking?
Design the rollback automation: which metrics trigger it, at what thresholds, and how do you avoid cascading rollbacks?