ETL vs ELT, what changed, and when is classic ETL still the right call?
Sounds like a definition question; it's actually a judgment question. The economics that flipped the industry to ELT, and the four cases (starting with PII) where transforming before load is still non-negotiable.
Updated Sep 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
Sounds like a definition question; it's actually a judgment question. The economics that flipped the industry to ELT, and the four cases (starting with PII) where transforming before load is still non-negotiable.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
