Why MPP?
For 30 years, micropayments failed because the payer was human. Now the payer is software.
The problem
Every API today requires an API key. That means creating an account, agreeing to terms, storing credentials, managing rate limits, rotating secrets. For a human developer, this is annoying. For an AI agent acting autonomously, it's a dead end.
Agents can write code, search the web, and reason through problems, but they can't sign up for an account. The entire API economy is gated behind a flow designed for humans sitting at keyboards.
The shift: payment as authentication
The Machine Payments Protocol embeds payment directly into the HTTP request-response cycle. An agent calls an endpoint, gets a 402 Payment Required response with payment details, submits payment proof, and receives data. No keys, no accounts, no vendor dashboards.
Payment becomes the authentication. If you can pay, you can use the API. This is a fundamentally different access model, one built for software, not people.
Why now?
Agents have no mental transaction cost
Humans hesitate, abandon carts, resent friction, and perform mental accounting before every small transaction. AI agents don't hesitate before paying $0.001 for an API call, and they don't abandon carts.
Meng Liu, Forrester, Why Stripe's MPP Signals A Turning Point For MicropaymentsThe economic layer was missing
Agents could read, reason, and act, but could not pay. Organizations that have built policy controls around agent code access now face the same requirement for spending authority.
Mitch Ashley, The Futurum Group, Stripe's MPP Gives AI Agents a Way to Spend Money Without Human HelpNew business models unlock
API providers can charge per call. Compute platforms offer pay-per-session. Data services bill per query. The subscription model was a workaround for payment friction. Remove the friction, and usage-based pricing becomes natural.
Security through constraints
Payments are scoped, time-limited, and context-bound. Each transaction carries only the authorization it needs. No stored credentials to leak, no API keys to rotate, no broad access tokens to revoke.
It uses existing rails
MPP isn't a new payment network. It works with stablecoins, card networks, and bank transfers. Visa released a card specification and SDK for MPP. The protocol is the interface; the settlement layer is your choice.
Visa, Card Specification & SDK for MPPOpen standard, not a platform
MPP is a protocol, like HTTP. Any service can implement it. Any client can pay through it. No single company controls the registry, the payment flow, or the terms. That's why mpp.land exists: to index everything on the open web.
The ecosystem
MPP is not alone. Multiple protocols are converging on the same insight: machines need native payment primitives.
MPP
By Stripe & Tempo. HTTP-native, uses 402 status code and x-payment-info in OpenAPI specs. Supports stablecoins, cards via Visa, and streaming payments. MPP is backwards compatible with x402.
x402
By Coinbase. Chain-agnostic approach to HTTP payments. Shares the 402 philosophy with a different implementation strategy. The x402 Foundation moved to the Linux Foundation in April 2026 with 20+ founding organizations.
AP2
By Google. Agent Payments Protocol using cryptographically-signed Mandates as proof of user intent. Designed as an extension to A2A and MCP protocols, with 60+ collaborating organizations.
Google Cloud blogmpp.land currently indexes MPP services. As the ecosystem matures, we aim to track compliant services across protocols.
See it in action
Browse 105 live services, scored for compliance and reliability.
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