Google is expanding its Universal Commerce Protocol (UCP) hub with a checkout path that favors merchant sites, not just Google-hosted transactions. For performance marketers and D2C brands, the update is a chance to reclaim the post-click experience and customer data that marketplace checkouts often absorb.
What the UCP update includes
The new cart transfer capability, called “Transfer to merchant cart” in Google’s developer docs, lets merchants turn on a path that moves a shopper’s cart from Google to the retailer’s own site to finish buying. It requires supporting the Cart API. The rollout is gradual in the U.S., with Australia and Canada expected early next year, according to a holiday shopping post from Ashish Gupta, Google’s VP and GM of Merchant Shopping.
Merchants with hub access can also test cart and checkout requests in a sandbox. Google says UCP already enables direct checkout for hundreds of thousands of brands and retailers across Google, and the hub now includes expanded checkout flow testing.
- Enable the Cart API if you have UCP hub access in Merchant Center.
- Use the sandbox to test cart and checkout requests before going live.
- Complete the technical setup and submit the interest form to join the gradual rollout.
- Check the UCP integration tab for analytics and testing options as they appear.
Why cart transfer matters for merchants
Earlier this year, retailers voiced frustrations about Google-hosted transactions: customers never visit the store, see accessory suggestions from other sellers, and feel less connected to the brand. Cart transfer responds by sending shoppers to the merchant’s checkout page with a ready cart. That keeps upsells, email capture, and post-purchase messaging on your own infrastructure.
Think of this as an “own the checkout” framework. If acquisition costs are rising, shifting even a portion of Google-driven buyers to a first-party checkout can improve margin, data quality, and lifetime value. Agencies should audit client Merchant Center UCP settings now, before the holiday rush and before Australia and Canada rollouts arrive.
Analytics, YouTube Business Agent, and AI insights
Google says analytics will soon be part of the UCP hub. The UCP Analytics Reporting dashboard, available to merchants with UCP enabled and the Performance role, tracks checkout behavior from the Buy button click to completed purchase, including average order value and cancellations. It also shows account linking information and top-selling UCP products, but the data isn’t available through the Merchant API yet.
Separately, Google is launching a U.S. beta for Business Agent on YouTube ads, letting qualifying retailers embed a branded agent so viewers can browse products and ask questions without leaving YouTube. The AI performance insights report is now generally available in Australia, Canada, India, New Zealand, and the U.S., but it covers organic AI traffic only and does not report clicks. Pair the two views: UCP analytics for conversion depth, AI insights for visibility and share of voice.
Source: Search Engine Journal
