AP2: verifiable mandates for authorization
AP2, the Agent Payments Protocol led by Google, focuses on proving that an agent was authorized to spend. It uses cryptographically signed mandates that capture user intent and the limits of what the agent may buy, so a merchant or payment provider can verify the agent acted within a real, attributable instruction. AP2 is about trust and accountability at the authorization layer, and it is designed to be payment-method agnostic. For the full specification, the current mandate model and the FIDO Alliance handover, see our guide to Google AP2.
ACP: standardized agentic checkout
The Agentic Commerce Protocol, developed by OpenAI and Stripe, standardizes how an agent completes a purchase with a merchant. It defines how product information, carts, and checkout flow between an AI surface and a seller so an agent can buy without a custom integration per store. ACP operates at the checkout and commerce layer, making merchant transactions interoperable for agents.
x402: HTTP 402 machine micropayments
In practice most agents reach x402 through a tool call, so it is worth reading this alongside how MCP payments work. x402, introduced by Coinbase and now governed by the Linux Foundation, revives the long-reserved HTTP 402 Payment Required status code to let machines pay for resources inline over HTTP. A server can respond with a 402 and a price, and the client settles instantly, typically with stablecoins, before the request proceeds. x402 targets the settlement layer for low-value, high-frequency agent and API payments. For the response format, the facilitator role and what changed in v2, see our full guide to the x402 protocol.
Where the card networks fit
These protocols are open standards, but the money still settles over a payment rail, and the two biggest card networks now have their own agentic programs that implement them. Visa Intelligent Commerce supports payments initiated through several of these protocols and issues scoped, tokenized card credentials to agents. Mastercard Agent Pay does the same with Mastercard Agentic Tokens and adds agent-to-agent settlement across cards, bank accounts and stablecoins. If you are weighing which rail to build on rather than which protocol, our comparison of Visa Intelligent Commerce vs Mastercard Agent Pay breaks down how they differ and what neither one governs. Both networks also joined the launch coalition for the Universal Commerce Protocol, the Google and Shopify standard announced in January 2026 that wraps catalog, cart, checkout, and orders into one specification and is documented as interoperable with AP2. That is the layer above the three here, and it is the one most US merchants will be asked about next.
How Agentspay fits across all three
These standards define how agents authorize, check out, and settle, but none of them decides whether a given spend should happen. Agentspay is the rail-neutral control plane that sits across them: it enforces policy, applies hard spend limits, pauses for human approval, and writes an immutable audit trail regardless of which protocol moves the money. You adopt AP2, ACP, or x402 as they fit, and keep one place that never moves money without policy.