Learn

Learn

The evergreen reference, arranged from the basics to the technical detail. New here? Start at the top and work down.

How it works

How agents pay, and each protocol in depth.

How AI Agents Pay

How AI agents actually pay: tokenization, signed mandates, passkeys and delegated authority, and the network products from Visa, Mastercard, American Express, PayPal, Stripe, and the x402 stablecoin rail. What is live versus announced.

AI Shopping Agent Authorization: Mandates, Tokens, Passkeys, And Liability

How payment authorization works when AI shopping agents buy for users: mandates, scoped tokens, passkeys, network agent programs, liability gaps, and merchant evidence.

ACP Explained: The Agentic Commerce Protocol

A neutral guide to the Agentic Commerce Protocol (ACP): what it is, who maintains it, how payment flows through a Shared Payment Token, what is actually live, and how it relates to AP2, MCP, and UCP.

AP2 Explained: The Agent Payments Protocol

A neutral guide to the Agent Payments Protocol (AP2): how it proves a user authorized an agent's purchase, the mandate model, its move to the FIDO Alliance, and how it relates to ACP, A2A, MCP, and x402.

AP2 vs Network Tokens: An Open Standard or the Card Networks' Own Rails?

A neutral comparison of AP2, the open agent payment-authorization standard, and the card networks' own agent-payment programs (Visa Intelligent Commerce, Mastercard Agent Pay, American Express): how they differ, where they overlap, and why they are converging rather than simply competing.

UCP Explained: The Universal Commerce Protocol

A neutral guide to the Universal Commerce Protocol (UCP): Google's open standard for the full agentic shopping journey, who governs it, how it relates to ACP and AP2, and what is actually live.

MCP Explained: The Model Context Protocol in Agentic Commerce

A neutral guide to the Model Context Protocol (MCP) and its role in agentic commerce: the discovery layer agents use to find and call a merchant's tools, how it composes with the commerce protocols, and how it shows up in payments.

A2A Explained: The Agent-to-Agent Protocol

A short, neutral guide to A2A, the Agent-to-Agent protocol: the open standard for agents to communicate and delegate to one another, and the coordination layer that AP2 and x402 build on in agentic commerce.

ACP vs UCP: Comparing the Two Agentic Commerce Checkout Standards

A neutral, side-by-side comparison of ACP and UCP, the two open agentic commerce checkout standards: who backs each, how their scope differs, what is live, how payment works, and whether a merchant should support one or both.

MPP Explained: The Machine Payments Protocol

A neutral guide to the Machine Payments Protocol (MPP): the open standard from Stripe and Tempo that lets AI agents pay for APIs, compute, and services programmatically, how it works, what it settles in, and how it relates to x402, ACP, and AP2.

x402 Explained: HTTP 402 for Machine-Native Payments

A neutral guide to x402: Coinbase's open protocol that revives the HTTP 402 status so software can pay software in stablecoins, how the facilitator model works, who governs it, and how it relates to MPP and AP2.

x402 vs MPP: Comparing the Machine-Native Payment Protocols

A neutral comparison of x402 and MPP, the two machine-native settlement standards for agents paying for APIs, compute, and services: what they share, how they differ in sponsor, settlement, and rails, and when to use each.

How to Prepare Your Product Catalog for Agentic Commerce

A practical, protocol-agnostic guide to getting your product data agent-ready: what 'agent-ready' means, the fields that matter most, why live-store parity is non-negotiable, where the feed goes, and how to curate and keep it current.