The race to build payment infrastructure for AI agents is accelerating, with Coinbase and Stripe emerging as two of the most visible contenders. Their competing frameworks, x402 and MPP, are designed to support a future in which software agents can initiate and complete transactions without direct human involvement.
HTTP 402 gets a second life
Both initiatives are built around the long-unused HTTP 402 Payment Required status code. The idea dates back to 1996, but it failed to gain traction because micropayments were impractical in an environment marked by high transaction costs and weak infrastructure. That picture is changing as stablecoins and Layer 2 networks make low-cost, high-frequency payments more realistic.
Two different approaches to machine payments
Coinbase launched x402 in May 2025 with a crypto-only design, highlighting zero protocol fees and open-source flexibility. The model is aimed at enabling native onchain payments between AI-driven services and agents. Stripe took a different route with MPP, introduced in March 2026, combining fiat support with compliance-focused features to appeal to enterprise users that need more familiar payment and regulatory tooling.
A broader competitive landscape
The field is not limited to these two companies. Visa and Mastercard are also moving into agent payments by extending their existing financial infrastructure. As the AI agent economy grows, the leading protocol will likely be the one that can balance technical efficiency, regulatory readiness, and enterprise adoption. For now, the contest highlights a larger shift: payment systems are being redesigned for a machine economy where autonomous software may become a major class of transacting users.