The Agent Payment Protocols Tracker

Ant International

An open-sourced agentic payment framework for wallets, super apps, and wearables that embeds a Know-Your-Agent digital-identity framework, with a 2026 Phase I rollout across ten Alipay+ wallets and seven acquirers.

Stripe and Tempo

A protocol for machine-to-machine payments over HTTP 402, co-authored by Stripe and Tempo. Stripe says it offers payment support for both MPP and x402. The MPP FAQ describes the relationship in its own words: both use HTTP 402, and the core x402 exact flows map directly onto MPP's charge intent. Status is recorded as spec-published because live usage could not be confirmed from a primary source.

Google, with Shopify, Etsy, Wayfair, Target, Walmart and others

An open-source agentic commerce standard whose Identity Linking capability lets a shopper connect retailer accounts via OAuth so agents transact with the user’s authenticated merchant identity and loyalty benefits. Adoption note, September 14, 2026: Worldline launched a UCP payment handler, one of the first in Europe, letting merchants declare a payment configuration once and accept agent-initiated purchases across UCP-connected AI platforms (Finextra). Adoption note, October 12, 2026: Newegg integrated UCP checkout, with purchases completing inside Google Search, AI Mode and Gemini via Google Pay and Newegg as merchant of record, joining the January co-developers Shopify, Etsy, Wayfair, Target and Walmart and launch endorsers such as Macy's (Google, January 11; Digital Commerce 360); the Major Matters scan of October 10 found 2 of the 92 largest US storefronts publishing a discoverable UCP profile.

OpenAI and Stripe

The open standard first used for Instant Checkout in ChatGPT, in which the agent passes a Shared Payment Token to the merchant so the order can be identified and accepted without the merchant receiving raw card credentials. Status note: on March 24, 2026 OpenAI discontinued the initial version of Instant Checkout, writing that it "did not offer the level of flexibility that we aspire to provide," and moved to merchants running their own checkout while ChatGPT handles product discovery (source: openai.com/index/powering-product-discovery-in-chatgpt). The protocol specification remains published.

Google, with 60+ payments and technology partners

An open protocol for agent-led payments in which each purchase is a set of cryptographically signed, tamper-evident Mandates built on verifiable credentials (Intent, Cart and Payment Mandates at launch; version 0.2 of the specification, released April 28, 2026, defines two types, the Checkout Mandate and the Payment Mandate). Status note: standardization work on AP2 has moved into the FIDO Alliance (source: fidoalliance.org/fido-alliance-agentic-ai), and the specification now lives at ap2-protocol.org/ap2/specification.

x402 Foundation (Linux Foundation); steering committee: Coinbase, Cloudflare, Stripe

The HTTP 402-based protocol that lets an agent pay per request programmatically, with no human and no checkout page, settling over stablecoin rails. Status note, September 18, 2026: the x402 Foundation launched operationally under the Linux Foundation on July 14, 2026 with 40 named members, and its Technical Steering Committee lists Coinbase, Cloudflare and Stripe. Tracked in depth, with sourced usage figures, in the Major Matters x402 Adoption Tracker at /x402.

Ant International, Mastercard and Visa

A collaboration on a Know-Your-Agent interoperability framework to streamline AI agent onboarding and identification across card networks, wallet ecosystems, agent platforms and marketplaces, each retaining its own verification.

Mastercard and Google

An open, standards-based framework (v0.1 draft, February 2026, with a Python reference implementation) that links a consumer’s identity, their instructions to an agent, and the transaction outcome into a tamper-resistant record.

Visa, co-developed with Cloudflare

A framework enabling AI agents to cryptographically identify themselves to merchants during agentic commerce transactions, with partners including Adyen, Ant International, Checkout.com, Coinbase, Fiserv, Microsoft, Shopify and Stripe.

Mastercard

An agentic payments program that registers and verifies AI agents and uses Agentic Tokens (an extension of tokenization) to bind a card credential to a specific agent, merchant scope, and consent.

Sierra and Meta, with Genesys, Instinct, Rocket, Shopify, Stripe and Walmart

An open standard for how a consumer's personal agent signs in to a business and acts for the customer, announced October 6, 2026. Built on OAuth: a guest mode for things like stock checks and returns policies, then a signed-in mode in which the customer chooses read-only or write access and the company decides what it exposes through its website, its APIs (MCP and OpenAPI) or its own agent. Payments are a stated later extension ("Payments extensions could let a personal agent complete a purchase without sharing credit card information"). A v0.1 specification is due in October 2026, with design workshops and a reference implementation to follow. OpenAI, Amazon and Anthropic are not founders.

Cloudflare (proposed), now under IETF standardization

A mechanism using HTTP Message Signatures and well-known key directories so bots and AI agents cryptographically identify themselves to origins instead of relying on IP addresses or user-agent strings; now being standardized by the IETF.