Reconciling Klaviyo Subscription Status: 63% Had Cancelled
A subscription brand's Klaviyo account marked customers active or cancelled, and 63% of the "active" ones had actually cancelled, some two years earlier. The integration sent the cancellation event but never updated the profile property. How we reconciled about 28,000 profiles against the client's data warehouse with Claude Code: a negative match, email then name-and-ZIP fallbacks, verification before any write, and the flow plus weekly job that keeps it from drifting again.