Live reference
Protocol Status Radar
A status map of the standards covered by this site. Scope and governance are taken from the linked primary sources. “Stable” is a project maturity label, not a security or deployment certification.
| Protocol | Maturity | Governance | Scope | Last source review |
|---|---|---|---|---|
| ACP Agentic Commerce Protocol | Beta / evolving | Founding maintainers OpenAI and Stripe, with a stated path toward broader community governance | Open standard connecting buyers, their AI agents and merchants; it powered Instant Checkout in ChatGPT from September 2025, and since March 2026 it carries product discovery, merchant feeds and promotions into ChatGPT while merchants run their own checkout | primary source |
| UCP Universal Commerce Protocol | Beta / evolving | Open-source project co-developed by Google, Shopify, Etsy, Wayfair, Target and Walmart; specification maintained on GitHub (Universal-Commerce-Protocol/ucp) | Open standard for agentic commerce across the full shopping journey (discovery, buying, post-purchase); Google announced a future checkout rollout in AI Mode and the Gemini app, with the retailer remaining seller of record | primary source |
| AP2 Agent Payments Protocol | Neutral governance | Announced and initially led by Google Cloud with more than 60 organizations; ownership transferred to the FIDO Alliance on 28 April 2026 to keep the protocol platform-agnostic and community-led; public technical specification on GitHub | An open, payment-agnostic protocol to securely initiate and transact agent-led payments across platforms; uses verifiable credentials / mandates to capture user intent | primary source |
| MCP Model Context Protocol | Stable | Introduced by Anthropic; named on 9 December 2025 as a founding technical contribution to the Agentic AI Foundation, a directed fund under the Linux Foundation, alongside Block's goose and OpenAI's AGENTS.md | An open standard that connects AI applications and agents to external systems (tools, data, business apps). It is the context/tool layer, not a payment protocol; commerce protocols such as AP2 and ACP build on or extend it | primary source |
| x402 x402 | Stable | Launched by Coinbase; the specification was transferred to the x402 Foundation (the coinbase/x402 repository is now a development fork); homepage x402.org | An open payment standard for internet-native payments built on the HTTP 402 (Payment Required) status code; transport-agnostic, designed for humans, apps and AI agents | primary source |
| TAP Trusted Agent Protocol | Beta / evolving | Published by Visa (Visa Developer Center and GitHub); Visa states alignment work with standards bodies IETF, OpenID Foundation and EMVCo | Trust framework for agentic commerce: lets merchants cryptographically verify approved AI agents (agent intent, consumer recognition, optional payment information) and distinguish them from malicious bots at checkout | primary source |
| Agent Pay Mastercard Agent Pay | Announced | Proprietary Mastercard program (not an open-source specification); Mastercard states collaboration with industry players to advance agentic payment standards | Agentic payments program: registered and verified AI agents transact on a consumer's behalf using Mastercard Agentic Tokens, with consumer controls, transaction transparency, fraud protection and dispute support | primary source |
| A2A Agent2Agent Protocol | Neutral governance | Linux Foundation Agent2Agent project (announced 23 June 2025 with Amazon Web Services, Cisco, Google, Microsoft, Salesforce, SAP and ServiceNow) | Open standard for agent-to-agent communication: lets AI agents from different vendors and frameworks discover each other, delegate tasks and coordinate work; complementary to MCP (agent-to-tool) | primary source |
| MPP Machine Payments Protocol | Beta / evolving | Open standard co-authored by Tempo and Stripe; specification published at mpp.dev | Internet-native machine payments: a specification for agents and services to coordinate payments programmatically (microtransactions, recurring payments, pay-per-request) against any HTTP or MCP addressable endpoint | primary source |
Need a decision tree rather than a status list? Start with the readiness diagnostic or the platform implementation guides.