Agentic commerce glossary

Plain, sourced definitions of the terms used across this site. Deep-link any entry.

Agentic commerce: Online commerce in which AI agents discover, decide and complete purchases on a person's behalf, rather than the person clicking through a storefront themselves.
Agentic checkout: The step where an AI agent finalizes a purchase with a merchant, passing order and payment details over a protocol such as ACP, while the merchant remains merchant of record.
ACP (Agentic Commerce Protocol): Open standard co-developed by OpenAI and Stripe (announced 29 Sep 2025, Apache 2.0) that powers Instant Checkout in ChatGPT.
UCP (Universal Commerce Protocol): Open standard launched by Google on 11 Jan 2026 with Shopify, Etsy, Wayfair, Target and Walmart (Apache 2.0), covering the agentic shopping journey end to end; compatible with A2A, AP2 and MCP.
AP2 (Agent Payments Protocol): Open, payment-agnostic protocol announced by Google on 16 Sep 2025 to authorize and execute agent-led payments; an extension of A2A and MCP.
MCP (Model Context Protocol): Open standard from Anthropic (25 Nov 2024, MIT, donated to the Linux Foundation in Dec 2025) that connects AI agents to tools and data. The context layer of the stack.
x402: Open payment standard from Coinbase (6 May 2025, Apache 2.0) that carries native stablecoin payments over HTTP using the 402 status code.
A2A (Agent2Agent): Open standard for communication between AI agents, created by Google (9 Apr 2025) and donated to the Linux Foundation (23 Jun 2025). AP2 is designed as an extension of A2A.
TAP (Trusted Agent Protocol): Visa framework (14 Oct 2025, with Cloudflare) that lets merchants cryptographically verify trusted AI agents at checkout, built on HTTP Message Signatures (RFC 9421).
Mastercard Agent Pay: Mastercard’s proprietary agentic payments program (29 Apr 2025): registered, verified AI agents pay on a consumer’s behalf using Mastercard Agentic Tokens.
MPP (Machine Payments Protocol): Open standard co-authored by Tempo and Stripe (18 Mar 2026) for programmatic agent payments over HTTP, in stablecoins or fiat via Shared Payment Tokens.
Instant Checkout: The in-chat purchase experience in ChatGPT, powered by ACP and built with Stripe, that lets users buy from merchants without leaving the conversation.
Shared Payment Token (SPT): A Stripe payment primitive that lets an application like ChatGPT initiate a payment scoped to a specific merchant and cart total without exposing the buyer's credentials.
Facilitator (x402): A service that verifies and settles x402 payments on-chain so that sellers do not need to run their own blockchain infrastructure.
Merchant of record: The entity legally responsible for a sale (payment, tax, fulfillment, support). Under ACP the merchant stays merchant of record; the agent only relays information.
Agent Pay for Machines (AP4M): Mastercard service launched on 10 June 2026 to permission, orchestrate and settle agent-to-agent payments and microtransactions at machine speed, with 30+ launch partners. An extension of Mastercard Agent Pay.
Visa Intelligent Commerce: Visa platform for agentic commerce that provides trust, controls and connectivity for AI agents to discover, initiate and complete transactions. Expanded at the Visa Payments Forum on 10 June 2026 with Agent Score, an Agentic Directory and a Large Transaction Model.
Agent Score (Visa): A Visa Intelligent Commerce capability announced on 10 June 2026 that lets a merchant evaluate whether AI agents can navigate, understand and complete tasks on the merchant website.
Agentic Directory (Visa): A Visa trust registry announced on 10 June 2026 so merchants know which AI agents can be trusted to transact on their sites, and agents know they are interacting with a legitimate merchant.
Machine-to-machine (M2M) payments: Payments initiated and settled entirely between software systems, with no human in the loop at the moment of payment. Mastercard Agent Pay for Machines and x402 target this pattern.
Tokenized credentials: A payment credential replaced by a token scoped to a merchant, amount or context, so an AI agent can pay without handling the real card number. Used by Visa (Intelligent Commerce) and as Mastercard Agentic Tokens.
Large Transaction Model (Visa): An AI capability Visa announced at its 10 June 2026 Payments Forum that applies AI to transaction authorization, part of Visa Intelligent Commerce.
Amazon Bedrock AgentCore Payments: An AWS capability (June 2026) that integrates Coinbase x402 so agents built on Bedrock can discover and pay for services, with USDC settlement on Base and Solana.