Google’s Universal Cart launched in the US on October 15, 2026, across Google Search and the Gemini app. Google’s launch post says checkout from the cart is “powered by the Universal Commerce Protocol (UCP)”. For a merchant, that makes UCP a path a Google shopper can actually reach, not just a spec.

What Google says shipped

From Google’s launch post:

  • The cart saves items from multiple retailers in one place, across Search (including AI Mode) and the Gemini app.
  • It sends price-drop and back-in-stock notifications, built on Google’s Shopping Graph.
  • It is built on Google Wallet, suggests payment methods and shows promo codes.
  • Shoppers can “securely check out with Google Pay in just a few taps” in the cart, or “transfer your items directly to the merchant’s cart to finish buying on their site”.
  • Named merchants: Nike, Sephora, Target, Ulta Beauty, Walmart, Wayfair and “many Shopify merchants”.
  • Either way, Google says shoppers get confirmations and support from the merchant, who “will remain the seller of record”.

What is still “soon”

Google’s separate retailer post is more cautious than the launch post. It says shoppers can try the checkout features “soon” across Nike, Sephora, Target, Ulta Beauty, Walmart, Wayfair and Shopify merchants such as Fenty and Steve Madden.

The same post says UCP-powered checkout “will roll out across Canada and Australia in the coming months, and later to the U.K.” Outside those markets it gives no date. Treat the merchant list as launch partners, not as proof that every listed store is transacting today.

How a store becomes reachable over UCP

The UCP specification defines discovery. A business publishes a profile at /.well-known/ucp, and a platform fetches it first, then negotiates capabilities with the business (UCP overview, in the spec repo). The example profile lists services over REST, MCP, A2A or embedded transports, and capabilities such as dev.ucp.shopping.checkout.

Google’s posts do not publish a merchant enrolment checklist for Universal Cart. They say Google “co-developed UCP”, and that brands that have “integrated UCP” get access to some of the new ad formats. What a given store must do beyond publishing a valid profile is not stated in the posts we fetched.

What this does not tell you

A published profile is a necessary signal, not proof that an agent can finish a purchase. As we covered in UCP score: manifest, not checkout, a manifest can declare a capability while the transaction behind it was never exercised.

If your store runs on Shopify, platform-level UCP handling is the thing to confirm; our coverage of the Shopify UCP cart migration shows where it already sits.

FAQ

Is Google Universal Cart available outside the US?

Not yet. Google’s launch post says it is rolling out in the US across Search and the Gemini app. Google’s retailer post says UCP-powered checkout will roll out across Canada and Australia in the coming months and later to the UK, with no EU date given.

Does Universal Cart replace my store’s checkout?

No. Google says shoppers can either pay with Google Pay inside the cart or transfer items to the merchant’s cart to finish on the merchant’s site. Google states the merchant remains the seller of record in both cases.

How does a Universal Cart agent discover my store’s UCP support?

Under the UCP specification, a business publishes its profile at /.well-known/ucp, and the platform fetches it to negotiate capabilities before any checkout call. If that file is missing or invalid, there is nothing for a UCP platform to negotiate with.

Sources

Agent readiness is decided at the transaction: a cart that can reach your store only helps if an agent can also finish the purchase there.