The Universal Commerce Protocol (UCP) is an open-source standard that lets AI agents discover products, build carts, negotiate terms, and complete purchases with any merchant. It covers the full commerce lifecycle. Co-developed by Google and Shopify, announced January 11, 2026 at NRF.
Co-developed by Google and Shopify. 50+ partners have endorsed it including Walmart, Target, Amazon, Meta, Microsoft, Salesforce, Visa, Mastercard, Stripe, Adyen, Best Buy, Macy's, Etsy, Wayfair, Booking.com, Marriott, Hilton, DoorDash, and Uber Eats. The steering committee was expanded at Google Marketing Live in May 2026 to include Amazon, Meta, Microsoft, and Salesforce.
Shopify merchants have production UCP support via Agentic Storefronts. Google surfaces (AI Mode in Search, Gemini) are in early access with limited US merchants. The spec is live but still evolving. Non-Shopify platforms are at various stages of implementation. UCP is expanding beyond shopping into Lodging and Food verticals.
Depends on your platform:
angeo/module-ucp module (beta, discovery only) or use the UCP Proxy.See our platform guides for step-by-step instructions.
It is a JSON file served at /.well-known/ucp on your domain that describes your store's UCP capabilities. Agents fetch it to discover what you support: protocol version, services, transports, capabilities, and payment handlers. Think of it like robots.txt but for AI commerce agents.
No. Implement only the transports you need. REST is the most common and straightforward. MCP is recommended if you want compatibility with Claude, Cursor, and MCP-compatible agents. A2A is for multi-agent scenarios. Embedded is for rendering your checkout UI inside agent surfaces.
UCP is payment-agnostic. It delegates to AP2 (Agent Payments Protocol), which supports any payment processor. Supported handlers include Stripe, Adyen, Braintree, PayPal, Checkout.com, Fiserv, Worldpay, and others. You declare your supported handlers in your UCP profile.
Yes. Unlike ACP (OpenAI/Stripe's protocol), UCP does not prescribe a payment processor. You can use Stripe, Adyen, Braintree, or any other processor that implements AP2.
UCP (Google/Shopify) covers the full commerce lifecycle and is payment-agnostic. ACP (OpenAI/Stripe) is focused on checkout and uses Stripe exclusively. UCP supports REST, MCP, A2A, and embedded transports. ACP supports REST and MCP. UCP is in early access on Google surfaces. ACP is in production on ChatGPT.
Yes. They are not mutually exclusive. A merchant can support both. The discovery mechanisms are independent. Many merchants will likely support both to reach both Google surfaces (UCP) and ChatGPT (ACP).
UCP uses a server-selects architecture. The agent sends its profile URL with each request. The merchant fetches (or uses cached) agent profile, computes the intersection of both parties' capabilities, and selects the active set. The merchant is in control of what gets activated.
An extension is an optional module that augments a capability. For example, dev.ucp.shopping.fulfillment extends dev.ucp.shopping.checkout. Extensions use the extends field and schema composition (allOf) to add fields to parent capabilities. Multi-parent extensions are supported.
UCP uses dated releases (YYYY-MM-DD format). The protocol version is negotiated on every request. If the agent's version does not match the merchant's version, the merchant checks supported_versions for a compatible profile. Capabilities version independently within a protocol version.
UCP defines an escalation flow. The merchant returns status: "requires_escalation" with a continue_url. The agent presents this URL to the buyer, who completes the required step in their browser. The agent can then resume the checkout or receive a webhook.
Yes. Use your own reverse-domain namespace (e.g. com.yourcompany.shopping.loyalty). The spec/schema URLs must be hosted on your domain (matching the namespace authority). You do not need permission from the UCP governing body for vendor capabilities.
All monetary amounts in UCP are in minor units (cents). For example, 26550 means $265.50. This avoids floating-point issues in JSON.
Three options:
See our agent building guide for details.
Any OpenAI-compatible endpoint works. gateway.fast is optimized for agentic workloads with fast models (MiMo UltraSpeed at 1,000 tok/s, GLM 5.2 Fast) at cost + 10%. Speed matters for commerce agents because they make multiple sequential API calls.
Yes. Agents must host a profile at a well-known URL and reference it on every UCP request (via UCP-Agent header for REST or meta.ucp-agent.profile for MCP). The profile lets merchants verify your agent and apply the right rate limits and tool access. Higher trust tiers unlock broader access.