Three announcements, three different scopes
OpenAI's September 2025 announcement described the Agentic Commerce Protocol (ACP) alongside Instant Checkout in ChatGPT. It covered how a buyer can confirm an eligible order in chat while the merchant continues to handle acceptance, payment processing, fulfilment and support.
Google's January 2026 announcement described the Universal Commerce Protocol (UCP) as covering a broader commerce journey, including discovery and post-purchase support, and outlined an initial eligible-retailer rollout. Visa's October 2025 Trusted Agent Protocol announcement focused on identifying trusted agents and interactions between agents and merchants. These are adjacent ecosystem efforts, not synonyms for one interchangeable standard.
What a merchant should check before adopting
Do not begin with a vendor acronym. Ask which buyer journey is in scope, which retailers and markets can use it today, what product and order data must be shared, who takes responsibility for fulfilment and support, and how the merchant can inspect or revoke an agent's authority.
Then examine the current technical specification, supported commerce platform, transaction model, customer-confirmation step, security and identity provisions, privacy obligations, fees, and exception handling. Confirm the current status directly with the relevant provider because rollout terms can change.
A protocol-neutral readiness checklist
Clean product information, accurate policies and human-governed release decisions matter whether a business adopts one protocol, several, or none. A retailer can improve the traceability of product claims and the clarity of its customer journey without claiming protocol support.
Treat any connector or compatibility claim as a specific implementation fact requiring evidence. A readiness review is not an integration, certification or guarantee of discoverability.
Keep the decision open
The market is changing quickly. Record the source and date of each platform statement, distinguish live capability from pilot or planned rollout, and re-check eligibility before committing engineering time. Avoid assuming that protocols interoperate or that a U.S.-first launch applies in another region.
Protocol Verification Table: ACP vs UCP vs Visa TAP
Compare the three prominent agentic commerce standards by technical dimension. Filter by architecture, checkout, payment delegation, or bot security to evaluate what each protocol specifies.
| Technical Dimension | Agentic Commerce Protocol (ACP)OpenAI & Stripe · Sept 2025 | Universal Commerce Protocol (UCP)Google & Industry · Jan 2026 | Visa Trusted Agent Protocol (TAP)Visa & Cloudflare · Oct 2025 |
|---|---|---|---|
Primary Architectural Focusarchitecture Protocols operate at different layers: Visa TAP validates the agent's identity, ACP enables conversational chat checkout, and UCP standardizes the entire merchant-to-agent lifecycle. | SupportedIn-chat checkout & feed sync Optimized for conversational single-item/multi-item purchases within ChatGPT via structured feeds and checkout... | SupportedFull shopping lifecycle standard Comprehensive protocol covering catalog search, multi-item carts, checkout, order management, lodging and food... | SupportedAgent authentication & trust layer Cryptographic signature framework based on HTTP Message Signatures (RFC 9421) to distinguish legitimate commer... |
Merchant of Record (MoR)checkout Across all three protocols, merchants do not lose their Merchant of Record status or customer relationship to the AI platform. | SupportedMerchant remains Merchant of Record Retailer handles orders, inventory, tax, fulfillment and customer service using their existing processing back... | SupportedMerchant remains Merchant of Record Explicit core principle: businesses retain complete ownership of buyer relationships, returns, and fulfillment... | SupportedMerchant remains Merchant of Record Visa facilitates secure agent transactions while settlement, order fulfillment, and dispute handling remain wi... |
Product Catalog Discovery Mechanismarchitecture To appear in conversational search, merchants must maintain high-integrity, structured feeds with variant-level SKU and pricing accuracy. | SupportedFile Upload / SFTP & Feed API Merchants provide JSON feeds or SFTP uploads conforming to ACP schema; ChatGPT indexes products organically ba... | SupportedREST & JSON-RPC Catalog APIs Standardized catalog search endpoint with filters, options, pagination, and real-time variant lookups across a... | Not in ScopeNot in scope Focuses on transaction trust and consumer recognition, not catalogue indexing or search ranking. |
Multi-Item Cart Buildingcheckout Complex carts with bundle logic or custom shipping rules require either robust UCP cart handling or deep backend webhook integration. | Scoped / EvolvingSingle-item first; carts expanding Launched with single-item Instant Checkout; multi-item cart capabilities are actively being added. | SupportedNative multi-item cart spec Includes dedicated Cart API with line-item management, tax calculations, shipping options, and continue-on-sit... | Not in ScopeNot in scope Does not define cart storage; handles agent transaction credentials at checkout moments. |
Payment Delegation & Tokenizationpayment AI agents do not pass plaintext credit card numbers; merchants must prepare gateways for delegated tokens or payment mandates. | SupportedStripe Shared Payment Tokens & Delegated Payment Spec Enables one-line integration for Stripe users; other payment processors consume time-bound shared payment toke... | SupportedAgent Payments Protocol (AP2) & Open Wallets Integrates with Google Pay, PayPal, and open AP2 payment mandates backed by verifiable cryptographic credentia... | SupportedVisa Intelligent Commerce Tokens & IOUs Passes hashed Visa Intelligent Commerce credentials, API/protocol tokens, or merchant account linking identifi... |
Bot Mitigation & Traffic Verificationsecurity If you use aggressive WAF or bot protection, implement RFC 9421 or protocol whitelist rules so legitimate buyer agents are not blocked. | Scoped / EvolvingClosed platform agent ID Orders arrive directly from verified OpenAI backend IPs and webhooks using TLS and HMAC headers. | SupportedOAuth 2.0 & Verifiable Mandates Standardized identity linking via OAuth 2.0 endpoints (/.well-known/oauth-authorization-server) and cryptograp... | SupportedHTTP Message Signatures (RFC 9421) Merchant-specific, time-bound cryptographic signatures that prevent replay attacks and allow bot filters (e.g.... |
Industry Scope Beyond Retailecosystem Travel, hospitality and restaurant businesses should track UCP's lodging/food drafts alongside retail standards. | Scoped / EvolvingPrimarily retail & DTC Current specifications focus on physical and digital commerce for retail goods and subscription services. | SupportedRetail, Lodging & Food Published draft specifications for hotel lodging (check-in/check-out, room rates) and food ordering with table... | SupportedCross-industry payment network Applies across all merchant categories accepting Visa intelligent commerce transactions globally. |
Ecosystem Endorsements (Sample)ecosystem Key platform players (like Shopify and Stripe) participate in multiple protocols, pointing toward eventual cross-protocol convergence. | SupportedOpenAI, Stripe, Etsy, Shopify Co-developed with Stripe; initial pilots with Etsy and Shopify merchant rollout. | SupportedGoogle, Walmart, Target, Shopify, Wayfair, etc. Co-developed by Google with over 30 retail and payment leaders including Adyen, Mastercard, Visa, Best Buy, an... | SupportedVisa, Cloudflare, Microsoft, Shopify, Adyen, Stripe Developed with Cloudflare with feedback from major acquirers, payment processors, and platforms. |
Sources and further reading
- OpenAI: Buy it in ChatGPT - Instant Checkout and the Agentic Commerce Protocol
- Google: New tech and tools for retailers to succeed in an agentic shopping era
- Visa: Trusted Agent Protocol announcement
Platform details and regulations change. Check the linked primary source before relying on a rollout, eligibility or compliance statement.