So what actually is Google’s Universal Commerce Protocol (UCP)?

Google’s UCP is an open source standard for online shopping. Like any standardized protocol, it works as a universally accepted set of rules, specifically in this instance to allow different stores, apps and platforms to talk to each other in the same way. That includes products, prices, carts, checkout, payments and order status — all structured so systems can interact with each other without cumbersome, custom integrations every time.

How does it work in practice?

Normally, each retailer, app or platform builds its own technical setup. One system might label a product a certain way, another might structure prices differently and another might track orders in its own format. When those systems try to connect, engineers often have to build a custom bridge between them — work that is slow, expensive and difficult to maintain.

UCP is meant to reduce that friction. It acts like a universal language for commerce data. If a store, a payments provider and a shopping app all use UCP, they already “speak” the same format. That means they can plug into each other with far less custom work because the information about products, carts and orders is organized in a predictable, shared way.

Sounds OK, but why do online retailers need this?

With online shopping heading toward agentic commerce, whereby AI agents will do a lot of the behind the scenes work for you, UCP makes it possible for them to still sell products without missing out on sales that don’t come through their website. For example, if a shopper wanted to buy a pair of Nike trainers in red, they could simply type in their request into Google’s Gemini, and Google’s UCP allows the AI agent to search various different retailers’ product inventories, find what you want, in your size and where stock is still available. It can do that because it defines a common format for how product and shopping data is organized, making it easier for an AI system to scan multiple retailers’ inventories in a consistent way instead of trying to decode dozens of different technical setups. In other words, the agent is not guessing what each store means, it’s reading information that follows the same structure.

A useful comparison is a personal assistant. If you give them clear, standardized details — what you want, your size and your budget — and they have access to organized store information, they can do the legwork and come back with a clear option: here’s the product, here’s the price, here’s where it’s in stock.

“What excited a lot of people about this announcement was Google’s ability to allow AI agents to get real-time pricing and inventory, connected to the merchant in a more programmatic way that doesn’t intermediate them,” said Jonathan Arena, founder of New Generation, a company which builds AI agents for e-commerce brands.

Who benefits from UCP (apart from Google)?

For retailers, it means they can sell stock a lot quicker and easier, than just simply relying on customers going to their particular website, clicking through all the pages, and hopefully ending up at checkout.

And likewise for users, it cuts out a lot of the middle steps. They can go into one platform and buy a product from anywhere, without the hassle of searching through different retailers, or being redirected to different pages, just so they can find what they want, in the size/color options, etc. they’re looking for, where stock is available, and ultimately be able to purchase.

“When commerce signals are expressed in a common protocol, retail media becomes more flexible,” said Michael Blanche, co-founder and co-CEO of customer acquisition platform Surfside. “Retailers don’t need fully vertical stacks to participate. Measurement can move closer to real business outcomes. Onsite, offsite, and in-store media can finally operate off the same underlying data.”

What are the challenges or concerns around it?

As great as it is, there are risks for retailers.

If UCP becomes widely adopted, it means Google has the upper hand because everything still sits within Google’s ecosystem. Which means the tech titan would sit in the middle of transactions, giving it the ability to influence who gets visibility, as well as shape rules, fees and priorities according to what Google thinks is the priority.

A widespread adoption of Google’s UCP could also become problematic because stores risk becoming too dependent on Google, similarly to how publishers relied on Google Search. And that reliance comes at a cost: if Google makes changes, it’ll be the retailers on the receiving end that may or may not suffer the consequences.

As eMarketer’s senior director, marketing and commerce, and tech briefings, Jeremy Goldman noted, universal, agent-mediated commerce reduces the importance of owned storefronts at the moment of purchase.

“When transactions occur inside Google’s environment, brands lose control over UX, merchandising, and post-purchase engagement,” he said. “Products risk becoming interchangeable inputs, ranked by availability, price, and fulfillment reliability rather than narrative or identity.”

Another concern is the customer relationship, and this is where UCP’s design really matters. By making product and checkout information easy for outside platforms and AI tools to use, UCP increases the chances that shopping happens inside environments run by companies like Google rather than on a retailer’s own site or app. 

In that scenario, the retailer still supplies the product but the platform owns most of the interaction with the shopper — the interface, the recommendations and much of the transaction data. Over time, that can weaken the direct link between retailer and customer. Fewer visits to owned sites mean fewer opportunities to shape the brand experience, collect first-party data, build loyalty and encourage additional purchases while the intermediary platform’s influence grows. 

“Brands may be reluctant — certainly initially — to adopt a technology that will allow customers to transact away from their owned properties, where the experience is controlled by them,” said Aaron Dicks, chief technology officer at performance marketing agency Impression. “This could be especially true for high consideration products or those in the luxury space, where retailers want to use their home platforms to showcase more of their wares to customers as they shop. Certain product categories might also fall foul of other requirements, such as regulatory or other restrictions.”