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x402 vs MPP: Comparing the Machine-Native Payment Protocols

Andrew McPherson

Depth · Core

Good for: Builders

x402 and MPP are the two machine-native settlement standards: both are built on the HTTP 402 “Payment Required” status, and both exist for software paying software, an agent paying for an API call, compute, data, or a digital service, rather than a person checking out. x402 is Coinbase’s stablecoin-focused protocol. MPP, the Machine Payments Protocol, is Stripe and Tempo’s, and settles in stablecoins as well as cards and buy-now-pay-later. They sit at the same layer of the stack, and Stripe supports both, so they are best understood as parallel options rather than a winner-take-all rivalry.

At a glance

x402MPP
Full namex402Machine Payments Protocol
Led byCoinbase, with CloudflareStripe and Tempo
Launched2025March 2026
Built onHTTP 402 “Payment Required”HTTP 402 “Payment Required”
Settles inStablecoins (for example USDC)Stablecoins, plus cards and buy-now-pay-later
RailsOn-chain, via a facilitatorTempo blockchain and Stripe (PaymentIntents API)
Governancex402 Foundation, under the Linux FoundationStripe and Tempo
Best forCrypto-native, on-chain settlementMixed settlement through one provider

What each one is

x402 revives the long-dormant HTTP 402 status so a service can demand payment inline: a client requests a resource, the server responds with a payment requirement, the client pays, and a facilitator verifies and settles the payment on-chain before the resource is delivered. It is stablecoin-native and aimed at a decentralized agent ecosystem. For the basics, see the glossary entry.

MPP standardizes the same kind of inline machine payment, but routes it through Stripe. A business already on Stripe can accept payments over MPP using the same PaymentIntents API it uses for human payments, and the funds settle into its normal Stripe balance, with the usual tax, fraud, reporting, and refund machinery. It pairs with Tempo, the blockchain Stripe uses for stablecoin settlement, while also supporting cards and buy-now-pay-later. For the detail, see MPP explained.

What they share

The important thing to hold onto is how much they have in common. Both build on the same web mechanism, HTTP 402, so an agent can settle a charge inside a single request. Both target the machine-to-machine lane: agent-to-agent payments, microtransactions, and per-call billing for APIs, compute, and content. And both are real today, sitting beneath the consumer-checkout protocols rather than competing with them. The difference is not the idea; it is who sponsors it and how the money actually moves.

How they differ

Three differences matter. Sponsorship: x402 comes from Coinbase and is crypto-native; MPP comes from Stripe and Tempo and is anchored in Stripe’s existing payments stack. Settlement breadth: x402 settles in stablecoins; MPP settles in stablecoins as well as cards and buy-now-pay-later, via Stripe’s Shared Payment Tokens, which makes it easier to fold machine payments into a business that already takes card payments. Rails: x402 settles on-chain through a facilitator the merchant does not have to operate; MPP settles through Tempo and Stripe, so the integration looks like the rest of Stripe. For how both relate to the wider money flow, see how AI agents pay.

Governance

x402 is organized through the x402 Foundation, now under the Linux Foundation, giving it neutral, multi-party stewardship. MPP is currently steered by its co-authors, Stripe and Tempo. That is a familiar pattern in agentic commerce: the crypto-native standard leans on a foundation early, while the provider-backed standard starts under its sponsors with the question of broader governance still open.

Which should you use?

Follow the settlement you need. If you want pure on-chain stablecoin settlement and a facilitator model, x402 fits, and its foundation governance may appeal if neutrality matters to you. If you want to accept machine payments alongside your existing card and buy-now-pay-later flows, through a single provider with familiar tooling, MPP through Stripe is the smaller lift. And because Stripe supports both, the choice is frequently not exclusive: you can pick based on whether you want stablecoin-only or mixed settlement, and revisit as the two standards mature.

FAQ

What is the difference between x402 and MPP? Both are HTTP 402-based machine settlement standards. x402 is Coinbase’s stablecoin-focused protocol, settling on-chain through a facilitator; MPP is Stripe and Tempo’s, settling in stablecoins as well as cards and buy-now-pay-later through Stripe.

Do they compete? They are parallel options at the same settlement layer, targeting the same machine-to-machine use cases. But Stripe supports both, so they are not mutually exclusive.

Which should I use? x402 for pure on-chain stablecoin settlement and a crypto-native facilitator model; MPP for accepting machine payments alongside existing card flows through Stripe. Stripe supporting both means the decision often comes down to stablecoin-only versus mixed settlement.

Primary sources

  1. x402 protocol (GitHub) · Coinbase
  2. Introducing the Machine Payments Protocol · Stripe, 2026-03-18
  3. MPP documentation · Stripe and Tempo