Reference
Protocols and programs
In short
12 protocols are profiled here, each with the matrix cells that describe it, the facts behind them and a source and read date for every claim. Together they hold 23 live cells, 12 pilot and 57 announced as of 4 Nov 2026. Live cells sit on ACP, UCP, Visa IC, Mastercard Agent Pay, x402.
Protocols and programs in the matrix
| Name | Operator | What it is | Stated cells |
|---|---|---|---|
| Agentic Commerce Protocol (ACP) | OpenAI, Stripe and Meta (lead maintainers) | An Apache 2.0 checkout protocol between an AI agent, a merchant and a payment provider; first shipped in ChatGPT Instant Checkout on 29 Sep 2025 and now used mainly for product feeds in ChatGPT. | 3 live, 2 pilot, 7 announced |
| Universal Commerce Protocol (UCP) | UCP Tech Council (Google, Shopify, Etsy, Target, Wayfair, Amazon, Meta, Microsoft, Salesforce, Stripe and others) | An Apache 2.0 protocol for discovery, cart, checkout and orders between agents and businesses, announced by Google and Shopify in January 2026; powers checkout in Google AI Mode and Gemini and Microsoft Copilot onboarding. | 10 live, 4 pilot, 6 announced |
| Agent Payments Protocol (AP2) | FIDO Alliance (donated by Google, April 2026) | A mandate-based protocol in which signed verifiable credentials record what the user authorised, giving issuers, merchants and networks an audit trail for human-present and human-not-present agent payments. | 0 live, 1 pilot, 10 announced |
| Visa Trusted Agent Protocol (TAP) | Visa | Visa's agent identity scheme: an agent signs each HTTP request with HTTP Message Signatures (Web Bot Auth) so a merchant or its CDN can tell a registered agent from a bot and receive consented user and payment identifiers. | 0 live, 1 pilot, 5 announced |
| Visa Intelligent Commerce (incl. Intelligent Commerce Connect) | Visa | Visa's program for agent payments: tokenised credentials for agents, cardholder-defined payment instructions, and since April 2026 Intelligent Commerce Connect, a single acceptance integration for TAP, MPP, ACP and UCP traffic. | 1 live, 1 pilot, 6 announced |
| Mastercard Agent Pay | Mastercard | Mastercard's agentic payments program: registered agents transact with Mastercard agentic tokens, merchants verify agents through Web Bot Auth at the CDN, and since 30 Sep 2026 issuers can test a probability score for AI-initiated transactions. | 1 live, 1 pilot, 8 announced |
| Mastercard Agent Pay for Machines (AP4M) | Mastercard | Mastercard's machine-to-machine payment service for agents buying digital services, built on x402 with MPP compatibility, settling across cards, accounts and stablecoins; Early Access opened 20 Oct 2026. | 0 live, 1 pilot, 7 announced |
| American Express Agentic Commerce Experiences (ACE) | American Express | American Express's developer kit for agent payments (agent registration, account enablement, intent, payment credentials, cart context), with Amex Agent Purchase Protection announced for agent errors. | 0 live, 0 pilot, 6 announced |
| x402 | x402 Foundation (Linux Foundation) | An HTTP 402 payment protocol: a server answers 402 with payment requirements, the client pays (mostly stablecoins on EVM chains and Solana, Lightning since Sep 2026) and retries; governed by the x402 Foundation. | 3 live, 0 pilot, 1 announced |
| Machine Payments Protocol (MPP) | Tempo and Stripe | An HTTP 402 protocol co-authored by Tempo and Stripe with challenge, credential and receipt messages and one-time, session and subscription intents, settling on Tempo stablecoins, Stripe tokens, cards or Lightning. | 2 live, 0 pilot, 0 announced |
| Stripe Link for agents (Link Agent Wallet) | Stripe | Stripe's consumer wallet exposed to agents: the agent creates a spend request, the user approves it, and Link returns a one-time credential or a saved Link payment at Link merchants; Meta Muse uses it. | 3 live, 0 pilot, 1 announced |
| Verifiable Intent (VI) | Mastercard, with Google; contributed to FIDO Alliance | An open SD-JWT credential format that chains credential provider, user and agent, binding user constraints (amount, merchants, items) so every party can prove what the agent was allowed to buy. | 0 live, 1 pilot, 0 announced |
See also the full matrix and the head-to-heads.
Sources
- agenticcommerce.dev/, read 4 Nov 2026
- Stripe: Developing an open standard for agentic commerce, read 4 Nov 2026
- ucp.dev/, read 4 Nov 2026
- shopify.com/news/ai-commerce-at-scale, read 4 Nov 2026
- AP2 protocol site, read 4 Nov 2026
- cloud.google.com/blog/products/ai-machine-learning/announcing-agents-to-payments-ap2-protocol, read 4 Nov 2026
- Visa Trusted Agent Protocol repository, read 4 Nov 2026
- Visa Introduces Trusted Agent Protocol, read 4 Nov 2026
- Visa Intelligent Commerce, read 4 Nov 2026
- Find and Buy with AI: Visa Unveils New Era of Commerce, read 4 Nov 2026
- Mastercard Agent Pay, read 4 Nov 2026
- mastercard.com/us/en/news-and-trends/press/2025/april/mastercard-unveils-agent-pay-pioneering-agentic-payments-technolog, read 4 Nov 2026
- ap4m.build/info, read 4 Nov 2026
- Mastercard launches Agent Pay for Machines, read 4 Nov 2026
- Amex Agentic Commerce Experiences, read 4 Nov 2026
- x402.org, read 4 Nov 2026
- Machine Payments Protocol, read 4 Nov 2026
- Stripe Link Agent Wallet docs, read 4 Nov 2026
- verifiableintent.dev, read 4 Nov 2026
- mastercard.com/us/en/news-and-trends/stories/2026/verifiable-intent.html, read 4 Nov 2026
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