When Would You Use Streaming?

The Decision Framework The interviewer wants to hear a number, not a vibe. Your first sentence should be: "What's the latency SLA?" Not "do we want real-time" - that's a wish, not a requirement. If they say "daily is fine," you just eliminated streaming from the conversation. That's a senior signal - you saved six months of unnecessary infrastructure. There are exactly four factors that drive the batch-vs-stream decision. Your answer should walk through all four. Miss any one of them and the interviewer knows you haven't built this in production. Here's the trap: volume alone doesn't decide this. A 10TB nightly load is a perfect batch job. A 100-event-per-second click stream that needs sub-second fraud detection is streaming. The interviewer wants to hear you reason about the combination o