Verifying Warranty Cards On-Chain: A Token-2022 Soulbound Receipt Checker

A repair-shop scenario illustrates the need to confirm whether a customer's warranty card is genuine without relying on screenshots or the holder's word. The article presents a verifier that checks a soulbound Token-2022 card using only public chain data, applying eight checks covering mint ownership, one-of-one supply, non-transferability, metadata location, issuing authority, warranty validity, order matching, and holder ownership. The verifier is a pure function over raw account data, making it reusable in servers, wallets, or agents. It returns every individual check result rather than a simple pass or fail, so staff can see exactly which requirement failed. The author notes the code is an unaudited, devnet-only educational example and that actual warranty decisions still depend on shop policy and consumer law.