Deep Dives
Technical architecture breakdowns and open-source specifications.
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The 4-party model for AI payments: how Visa and Mastercard rebuilt the rails
The traditional 4-party model was designed for humans. Here is how each of its five actors changes when an AI agent initiates the transaction — and how Visa and Mastercard built different answers to the same problem.
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How an AI agent buys something: the complete technical breakdown
HTTP signatures, agent-bound tokens, ISO 8583 field modifications, the VIC API call sequence, and the protocol ecosystem — TAP, x402, AP2.