About an hour. It was easy, but not that easy; kinda hard, but not hard, you know. Would I do an interview here again? Maybe. Who knows? But that is life.

Design a 3-tier web app (EC2, RDS, Scaling Groups, etc).

Repeat with Lambda and API Gateway.

Check for monitoring, logging, and scaling.

Ask about S3 tiers.

Ask simple things like: What are important considerations when developing a new API? Ask about OWASP vulnerabilities.

'You are on call and are told "the website is slow". How would you diagnose?' (Logs, network, scaling, monitoring, etc.)

Ask them to describe the latest thing they worked on and diagram it out/explain it. They should be able to. As they go, it might lead to more questions ('What does this part do?').