Interview Question
Design a secure large-file upload flow without proxying every byte through the API.
What a Strong Answer Should Cover
- Narrow authorization scope
- Direct object storage upload
- Treat uploads as untrusted
- Async validation and isolation
- Audit and lifecycle controls
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
- Where is the trust boundary?
- How would you prevent malicious or oversized uploads?
- What would you audit and retain?
What the interviewer is testing
- Requirements and constraints
- Architecture and trade-offs
- Reliability, security, cost, and operations
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.