Google used its I/O 2026 stage to push agentic shopping from demo to deployment, unveiling Universal Cart — a Gemini-powered shopping hub that works across merchants and services — and expanding the Universal Commerce Protocol (UCP), the open standard it co-built with major retailers so AI agents can discover, compare, and complete purchases on a shopper's behalf.
Key Highlights
- Universal Cart is a single, Gemini-powered cart that works across retailers and Google surfaces, from Search to Gemini
- It rolls out across Search (AI Mode) and the Gemini app in the U.S. this summer, with YouTube and Gmail to follow
- Checkout completes with Google Pay or by transferring the cart to the merchant's own site
- The Universal Commerce Protocol (UCP) is an open, community-driven standard co-developed with Shopify, Etsy, Wayfair, Target, and Walmart
- The Agent Payments Protocol (AP2) lets shoppers set strict brand, product, and spending limits before an agent ever pays
- Participating merchants include Nike, Sephora, Target, Walmart, Wayfair, and Shopify brands such as Fenty and Steve Madden
One Cart Across the Whole Web
Universal Cart is Google's attempt to collapse the fragmented checkout experience into a single hub. Powered by Gemini models, it lets shoppers save products from different retailers into one cart while browsing Search, chatting with Gemini, watching YouTube, or reading Gmail. The assistant does more than hold items: it finds deals, tracks price drops, alerts users on restocks, flags product incompatibilities, and suggests alternatives.
When it is time to buy, shoppers can check out with Google Pay using saved payment methods in Google Wallet, or transfer the cart to the merchant's own site to finish the purchase. Universal Cart begins rolling out across Search and the Gemini app in the U.S. this summer, with YouTube and Gmail to follow.
The Protocol Underneath: UCP
The cart is the consumer-facing surface, but the strategically important piece is the Universal Commerce Protocol. UCP is an open, community-driven standard designed to give AI agents, businesses, and payment providers a common language across the entire shopping journey — discovery, buying, and post-purchase support.
Google co-developed UCP with Shopify, Etsy, Wayfair, Target, and Walmart, and more than 20 additional ecosystem participants have endorsed it, including Adyen, American Express, Best Buy, Flipkart, Macy's, Mastercard, Stripe, The Home Depot, Visa, and Zalando. Critically, UCP is built to interoperate with other emerging agent standards: Agent2Agent (A2A), the Agent Payments Protocol (AP2), and the Model Context Protocol (MCP). That positions UCP less as a walled garden and more as connective tissue for an agentic commerce web.
Who Pays — and With What Guardrails
The thorniest question in agentic commerce is trust: how do you let software spend your money without losing control? Google's answer is the Agent Payments Protocol. AP2 lets an agent make secure payments on a user's behalf, but only inside boundaries the user sets — specifying allowed brands, specific products, and spending limits in advance.
AP2 creates transparent, verifiable links between the user, the merchant, and the payment processor, using privacy-preserving technology and tamper-proof digital mandates so every agent-initiated transaction is auditable. Google says AP2 will arrive across its products in the coming months, starting with the Gemini Spark personal agent. On the payments side, Google is also adding buy-now-pay-later options from Affirm and Klarna directly inside Google Pay.
Impact
For retailers, UCP reframes the storefront. Instead of optimizing only for a human clicking through a website, brands now have to be legible to agents that read catalogs, compare options, and trigger checkout programmatically. Early adopters — Nike, Sephora, Target, Walmart, Wayfair, and Shopify merchants like Fenty and Steve Madden — get a head start on that shift.
The move also intensifies a standards race. Agentic payments and commerce protocols are quickly becoming the layer where platforms compete, and Google's decision to make UCP open and interoperable with A2A, AP2, and MCP is a bid to set the default rails before rivals do. "We believe in an agentic commerce future that is open, collaborative and built for everyone to succeed," said Vidhya Srinivasan, VP and GM of Ads and Commerce at Google.
What's Next
Universal Cart and UCP-powered checkout are launching in the U.S. first, with expansion to Canada and Australia in the coming months and the U.K. later. Google is also taking UCP beyond physical goods into new verticals, including hotel booking — directly from AI Mode — and local food delivery. As agents move from answering questions to completing transactions, the cart may become the most contested piece of real estate on the web.
Source: Google