You're Not Interviewing for the Job. You're Auditioning for the Job Title

Ha. I like to give a systems design scenario that rewards simplicity. Candidates who complexify it (usually in very predictable ways) get rejected. The few who see the simple path have been great hires. Because they also asked the right questions.

Thank you! What are the right questions for a candidate to ask?

As a candidate, I feel that I should ask the interviewer if they're seeking a simple solution or a very scalable one. In this way, I can try to tune the response to the specific interviewer's expectations.

In this case, the most scalable is the simplest. Do the math on where errors can occur and accumulate, storage costs, latency, where rate-limiting can haunt you. The "throw in every feature you learned in certifications" will mess it all up.