Interview Question
A production API suddenly becomes slow. Walk through the first five things you would check before changing anything.
What a Strong Answer Should Cover
- Confirm the symptom and time window
- Check scope and affected users
- Review recent changes
- Compare application and dependency health
- Use evidence before selecting a fix
Common Mistakes
- Jumping to a technology before clarifying the problem
- Explaining the solution without the reasoning or trade-offs
- Omitting verification, failure handling, or prevention
Interviewer Follow-ups
- What evidence would make you change your hypothesis?
- What would you do if the issue disappears before you isolate it?
- How would you prevent a repeat incident?
What the interviewer is testing
- Problem isolation and evidence-based reasoning
- Safe mitigation and verification
- Prevention and operational learning
Real-World Sample Answer
A strong real-world response should connect requirements to engineering decisions, explain why the chosen approach fits the constraints, and make failure, security, cost, observability, and verification explicit.