You're replacing a customer's live scoring model with a better one. Design the rollout so nothing blows up.
Offline wins don't justify big-bang swaps, models fail in ways staging never shows. The shadow → canary → ramp playbook, what to compare at each stage, and the rollback discipline that keeps customer trust.
Updated Aug 2026 · Grounded in real Forward Deployed Engineer interview loops and written to a senior-engineer editorial bar.
Offline wins don't justify big-bang swaps, models fail in ways staging never shows. The shadow → canary → ramp playbook, what to compare at each stage, and the rollback discipline that keeps customer trust.
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.
