To support a robust Zcash payment ecosystem, vendors need a way to issue reliable payment requests. ZIP321 addresses this by allowing payment addresses, amounts (in ZEC), and memos to be encoded in URIs and QR codes. However, it only supports amounts denominated in ZEC, which creates friction when goods or services are priced in fiat currencies. Users must manually convert fiat to ZEC using exchange rates, increasing the risk of miscalculations.
In trusted environments—like clinics, offices, small shops, honor system stands—this is often handled by displaying a printed QR code and relying on the payee to enter the fiat amount into their wallet which helps determine the ZEC amount by using its internal exchange rate. While effective, because the URI lacks any reference to the original fiat amount or currency it forces the user to manually enter the amount or calculate the ZEC themselves. It also makes the wallets records and intent of the payment unclear and harder to verify later.
To improve usability and accuracy, ZIP321 should be extended to support fiat-denominated payment requests, such as with amount=100¤cy=USD. This would allow wallets to compute the correct ZEC amount automatically while preserving the pricing context.
