Interoperability Powers Stablecoin Payment Rails

Interoperability is the control point that turns stablecoins from a niche balance type into real payment infrastructure. The hard part is not creating another token or wallet. The hard part is making many chains, issuers, wallets, banks, and card networks work together so a user can hold one form of value and spend or move it anywhere. That is why players like Rain are building card and settlement layers, not just wallets or coins.

• The fragmentation is real on both sides. In the document, Rain describes separate blockchains, issuers, wallets, and fiat apps that cannot talk to each other cleanly. Circle built CCTP specifically to move native USDC across chains by burning on one chain and minting on another, which shows that even within one issuer, interoperability needs dedicated infrastructure.
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• Card networks are becoming the bridge into everyday spending. Rain partnered with Visa on onchain credit cards, and later expanded support to Solana, Tron, and Stellar so partners can launch one card program across multiple chains. Mastercard and MoonPay are doing a similar thing by linking stablecoin balances to cards accepted at Mastercard merchants worldwide.
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• The same pattern is showing up in fiat wallets. PayPal World now connects PayPal, Venmo, and other payment systems so users can send money across previously closed networks. That is the fiat analogue of what stablecoin infrastructure companies are trying to build across wallets, rails, and settlement systems.
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Over the next few years, the winners in digital money will look less like standalone wallet apps and more like translation layers for money. They will route value across chains, convert between stablecoins and fiat, attach better payment data, and plug into card and bank networks. As that happens, stablecoins stop being a separate category and start becoming another settlement rail inside mainstream fintech.