When to Say 'I'd Use Redis Instead'

The most impressive thing a mid-level candidate can say in a dict interview is: 'The in-memory dict works for this scale, but if the lookup table grows beyond RAM or needs to be shared across multiple worker processes, the natural escalation is Redis.' This single sentence signals architectural maturity — you're thinking about where the solution breaks, not just how it works in the happy path. Thread Safety — The Production Concern Interviewers Test For