MPP was co-authored by Stripe and Tempo and launched on 18 March 2026 as an open standard. The specification is published at mpp.dev, and Stripe lets businesses accept MPP payments through its existing PaymentIntents API.

MPP Explained: The Machine Payments Protocol

Q: How is MPP different from x402?

Both are machine-native settlement standards aimed at software-to-software payments rather than consumer checkout. x402 is Coinbase's protocol reviving the HTTP 402 status for stablecoin payments; MPP is Stripe and Tempo's protocol, which settles in stablecoins as well as cards and buy-now-pay-later via Shared Payment Tokens. Stripe supports both.

Q: Is MPP a checkout protocol like ACP or UCP?

No. MPP sits at the settlement layer, for agents paying for APIs, compute, and digital services, often as microtransactions or recurring payments. ACP and UCP are commerce protocols for the consumer shopping journey. MPP composes beneath or alongside them rather than competing.

The Machine Payments Protocol (MPP) is an open standard for letting an AI agent pay for something on its own, without a person entering card details or clicking a checkout button. It is built for the kinds of purchases agents actually make: paying for an API call, renting compute, buying access to a piece of data, or settling a small recurring charge. MPP is a settlement-layer protocol, not a consumer checkout standard.

Who is behind it

MPP was co-authored by Stripe and Tempo and launched on 18 March 2026. It is published as an open standard, with the specification at mpp.dev. Tempo is the blockchain Stripe pairs with MPP for stablecoin settlement, and Stripe provides the merchant side: businesses already on Stripe can accept payments over MPP using the same PaymentIntents API they use for human payments.

The problem MPP sets out to solve is that today’s financial tools were built for people. To buy something, an agent often has to create an account, read a pricing page, choose a plan, enter payment details, and set up billing, steps that usually need a human. MPP replaces that with a programmatic handshake an agent can complete by itself.

What MPP actually does

MPP standardizes the payment conversation between an agent and a service. The flow is deliberately simple: an agent requests a resource from a service, an API, a Model Context Protocol (MCP) endpoint, or any HTTP-addressable endpoint; the service responds with a payment request; the agent authorizes the payment; and the resource is delivered to the agent.

For a business accepting MPP through Stripe, these payments appear in the Stripe API and Dashboard like any other transaction. Funds settle into the business’s existing balance, in its default currency, on its normal payout schedule, and the usual Stripe machinery applies, including tax calculation, fraud protection, reporting, accounting integrations, and refunds. Payment can be made in stablecoins as well as cards and buy-now-pay-later methods, via Stripe’s Shared Payment Tokens.

Where it sits in the stack

MPP lives at the settlement layer, the part of the stack concerned with how value actually moves. Both MPP and x402 build on the same web mechanism, the long-dormant HTTP “402 Payment Required” status, so an agent can settle a charge inside a single request; the difference is sponsorship and rails, not the underlying method. x402 is Coinbase’s stablecoin-focused version. The two are best understood as parallel machine-native options rather than a commerce protocol versus a payment one: both target agent-to-agent and micro-transaction use cases, and Stripe explicitly supports both MPP and x402. For a side-by-side, see x402 vs MPP.

It is just as important to be clear about what MPP is not. It is not a checkout protocol for the consumer shopping journey, that is the job of ACP and UCP. It is not a discovery layer, that is MCP. And it is not a payment-authorization and trust framework like AP2. MPP composes beneath or alongside those layers. For the full picture, see the protocol stack.

What is actually live

MPP is live infrastructure on Stripe, and the launch came with named businesses already using it rather than just intentions. Browserbase lets agents spin up headless browsers and pay per session. PostalForm helps agents pay to print and send physical mail. Prospect Butcher Co. lets agents order sandwiches for pickup or delivery in New York City. Agents can also contribute programmatically to Stripe Climate. Parallel Web Systems uses machine payments so agents can pay per API call for web access.

The honest caveat is the same one that applies across agentic commerce: this is early, and it sits in the machine-to-machine lane, not retail checkout. MPP makes agent-initiated payments for services real and easy to accept on Stripe, but the broad ecosystem of agents and services transacting over it is still forming.

What it means for you

If you sell APIs, compute, data, or other digital services, MPP is the standard that lets agents become paying customers without a human in the loop, and if you are already on Stripe, accepting it is a small lift. If you are a builder, treat MPP as one of two settlement options for machine-native payments, alongside x402, and choose per use case. And if you are mapping the landscape, file MPP under settlement, next to x402, not as another contender at the checkout layer.

FAQ

Who created MPP? Stripe and Tempo co-authored it, launched 18 March 2026, with the spec at mpp.dev and acceptance available through Stripe’s PaymentIntents API.

How is MPP different from x402? Both are machine-native settlement standards for software-to-software payments, and both build on the HTTP “402 Payment Required” status. x402 is Coinbase’s stablecoin-focused version; MPP is Stripe and Tempo’s, settling in stablecoins as well as cards and buy-now-pay-later. Stripe supports both.

Is MPP a checkout protocol like ACP or UCP? No. It is a settlement-layer protocol for agents paying for APIs, compute, and services. ACP and UCP handle the consumer shopping journey; MPP composes beneath or alongside them.