Behavioral: Conflict with a PM

Interviewer

Tell me about a time you disagreed with a product manager on a technical approach.

Candidate

In my last role, our PM wanted to launch a real-time collaborative feature using existing REST polling to hit a tight deadline. I disagreed because load testing showed the database would buckle under the polling volume if adoption hit targets. Instead of just saying no, I spent half a day prototyping a WebSocket layer using Redis PubSub. I presented a comparison matrix: time-to-market, infrastructure cost, and user latency for both approaches. The PM saw that WebSockets added only 3 days but reduced server load by 80%. They agreed to adjust the launch date. The feature scaled to 50k concurrent users with zero downtime.

Interviewer

How did you maintain the relationship after disagreeing?

Candidate

I made sure the disagreement was framed around data, not opinion. By bringing a prototype and real metrics, it became a collaborative decision rather than a conflict. After launch, I publicly credited the PM for the successful timeline adjustment. We worked even better together afterward - they started coming to me earlier in their planning process.