Explainer · TIER_B
x402 vs MPP
Two HTTP 402 families. Different payloads, facilitators, and settlement stories.
zFinia published 7 September 2026
x402, launched publicly by Coinbase in May 2025, typically settles stablecoins through a facilitator such as CDP. MPP, co-authored by Stripe and Tempo in March 2026, is designed to be rail-agnostic including cards and stablecoins into existing merchant balances.
Cover both. Do not pretend they are the same protocol. Routing is a product.