Why Marketplace Platforms Should Settle Vendor Payments After Delivery, Not at Checkout

A software engineer who built a settlement service for a multi-vendor platform argues that crediting vendors at the moment of payment is a costly design mistake. Splitting money on payment success means any subsequent refund can become a collections problem if the vendor's funds have already been paid out. The recommended approach anchors vendor billing to a delivered_at timestamp plus a configured return window, ensuring funds are only released once the buyer's refund period has expired without incident. A SQL query from the live service enforces three conditions before a payout row is eligible: it must be unbilled, not excluded, and past the return window since delivery. The author contends this escrow-style model is not just good practice but the fundamental purpose of the data design in marketplace payment systems.