Universal Commerce Protocol (UCP): What You Need to Know

Google dropped a major update to the Universal Commerce Protocol (UCP) in March 2026. 

UCP is an open standard that helps AI agents communicate with ecommerce stores to complete purchases on users’ behalf.

For example, when users ask Gemini, “find me the best running shoes under $100,” the AI agent can fire up a search, browse products across retailers, and present the best options. If the user gives a go-ahead, it can then complete the purchase. All this is made possible through UCP.

With this new update in March 2026, UCP is gaining several new capabilities, including cart support and product catalog access. Google is also simplifying the onboarding process through Merchant Center to bring in more retailers. Right now, UCP-powered checkout is available to eligible U.S.-based merchants, with global expansion planned throughout 2026. 

In this article, we’ll unpack what UCP is, what the March 2026 updates change, and what ecommerce businesses should do to prepare.

What Is UCP?

UCP is an open-source, vendor-agnostic standard that defines a common language for AI agents and merchant stores to communicate with each other. 

It was co-developed by Google with industry partners including Shopify, Etsy, Wayfair, Target, and Walmart, and endorsed by more than 20 global partners like Visa, Mastercard, Stripe, and Adyen. 

While Google built the first reference implementation (powering checkout in AI Mode and the Gemini app), UCP itself is designed to work across any AI platform, retailer, or payment provider. 

For an agent like Gemini to browse products, compare options, and complete a purchase on your behalf, it needs a reliable, standardized way to talk to your store’s backend. 

Here’s a visualization that should help put things into perspective:

Let’s break this down step by step:

• On the left, you have consumer surfaces (like AI Mode on Google Search, Gemini app, etc.) where shoppers go to search for products
• The UCP sits in the middle to handle communication between those surfaces (which are agentic) and your store. UCP provides a set of capabilities for store owners that they can pick and choose from depending on what they want to support. More on this later. 
• On the right, you have your store’s backend that the agent talks to. Your store's backend is responsible for things like processing orders, managing inventory, and arranging delivery.

Currently, UCP checkout uses Google Pay with payment methods stored in Google Wallet. Google has confirmed PayPal support is forthcoming. UCP also supports two integration paths: a native checkout where the AI surface handles the checkout UI, and an embedded option that lets you maintain your own customized checkout experience. 

Now, let’s look at the individual capabilities that UCP unlocks.

What Are UCP’s Capabilities?

UCP currently offers five capabilities that enable the agentic shopping experience. Three were available at launch in January 2026, and two were added in the March 2026 update: 

1. Checkout: Enables agents to initiate and complete the checkout process on a shopper’s behalf. At launch, this was limited to single-item guest checkout. The March 2026 update expanded this to support richer transaction flows. 
2. Identity linking: Lets shoppers get the same loyalty or member benefits they would on a retailer’s site, like discounted pricing or free shipping
3. Order management: Gives agents the ability to retrieve and manage order details after a purchase is made, including tracking and status updates
4. Cart: Allows agents to add one or more products to a cart at once, just as a shopper normally would 
5. Product discovery (catalog): Gives agents the ability to pull real-time product details from your store, including variants, inventory, and pricing, so shoppers always see accurate information

Google has also announced a simplified UCP onboarding process through Merchant Center, designed to bring in more retailers of all sizes. Platform partners Salesforce, Stripe, and Commerce Inc. have confirmed they’ll implement UCP support in the near future, which will lower the technical barrier for merchants on those platforms. 

Now that we’ve covered how UCP works, let’s look at why it matters for your business. 

The Future of Ecommerce Is Agentic

The next major shift in ecommerce is agentic commerce: shopping experiences where AI agents handle the buying journey on a shopper’s behalf, from product discovery through checkout. The shopper tells Gemini (or ChatGPT, or whatever agent they prefer) what they want, and the agent takes it from there. 

Think about how shopping behavior has shifted before. People moved from physical stores to websites. Then mobile. Then social commerce. Each shift changed something fundamental, and the businesses that adapted early came out ahead.

Agentic commerce follows the same pattern.

If your store isn't set up to communicate with the AI agent, it may not know you exist. And if it doesn't know you exist, it won't recommend you. The shopper will simply buy from someone else.

This is why UCP matters. It's the foundation your store needs to participate in the agentic shopping experience.

Not sure whether your brand shows up when shoppers use AI platforms to research and discover products? Run a quick check with Semrush’s AI Visibility Toolkit to find out. The tool tracks how often your brand is mentioned and cited across AI-generated answers on platforms like ChatGPT, Google AI Overviews, AI Mode, and Gemini

Open the tool, enter your domain, and click “Check AI Visibility.”

You'll see your overall AI visibility score (a 0-100 benchmark), which platforms are mentioning your brand, and how you compare against competitors.

You can also explore topic opportunities—prompts where competitors appear but you don’t—to identify gaps in your AI visibility. 

Try the tool today to check your visibility.

How Agentic AI Expands Ecommerce SEO

Agentic AI requires ecommerce teams to optimize for a new set of surfaces and signals, but it builds on your existing SEO foundations rather than replacing them. 

The quality content you've created, the product data you've maintained, and the brand authority you've built all still matter. 

There are a few additional things you'll need to layer on top of those foundations. And they all tie back to UCP.

1. Having a Merchant Center Account Is Necessary

To participate in Google’s UCP-powered checkout, you need an active Google Merchant Center account with products eligible for checkout. If you don’t have one yet, follow this tutorial to get set up.

If you already have a Merchant Center account, here’s what’s specifically required for UCP eligibility:

• Return policies: Your return policies need to be clearly defined in Merchant Center
• Customer support information: You need to provide your support contact details. The AI agent needs confidence that the shopper will be taken care of post-purchase.
• Agentic checkout eligibility: Add the native_commerce attribute to your product feed for each product you want eligible for UCP-powered checkout. This is a product-level setting: You choose which items to enable, and it doesn’t affect your existing Shopping ads or free listings. Google recommends adding it through supplemental data source in Merchant Center rather than modifying your primary feed, to avoid formatting issues that could affect standard product ingestion. 
• Product identifiers and compliance: Each product needs an ID that maps to the product ID your checkout API uses. If your Merchant Center product IDs don’t match your checkout system, use the merchant_item_id attribute to map them. For products requiring legal warnings (like Prop 65 disclosures), include the consumer_notice attribute. 
• Conversational commerce attributes (coming soon): Google has announced dozens of new data attributes for Merchant Center designed for AI-driven discovery, including fields for product Q&A answers, compatible accessories, and product substitutes. These help AI agents answer specific shopper questions like “is this jacket waterproof?” Google is rolling these out with a small group of retailers first, with broader availability expected in the coming months. Start planning how you’ll populate these fields so you’re ready when access expands. 

Google announced a simplified UCP onboarding process through Merchant Center in March, 2026, designed to bring in retailers of all sizes. This is rolling out over the coming months. For now, UCP checkout remains available to selected merchants through an early access program—submit the merchant interest form to get in line for access as Google expands. 

2. Data Consistency Matters a Lot

Data consistency is a hard requirement for being included in agentic shopping experiences.

A human shopper might overlook a price mismatch between your product page and your feed, or not notice a missing return policy. An AI agent won’t.

So run a thorough audit across every surface that the agent can use:

• Make sure your products are described consistently across your site, Merchant Center feed, and third-party sites (e.g., Amazon) 
• Make sure that your return policy, shipping information, and customer support details match across your feed and your site
• Check that your on-site structured data matches with the actual production information

If there are any inconsistencies or gaps, fix them immediately.

3. Structured Data Becomes Crucial

Structured data has always been important for ecommerce SEO, and that importance only increases with agentic commerce. 

Google continuously compares what you tell it in Merchant Center with what’s on your website. When those two don’t match, trust drops and visibility suffers. AI agents rely on accurate product data to make confident recommendations, so any inconsistency between your onsite structured data and your Merchant Center feed could hurt your chances of being surfaced. 

So make sure every product page on your site has accurate, up-to-date structured data markup.

Haven’t even implemented this markup on your site yet? Please make this a priority.

Here’s the markup for a sample product page:

Replace the placeholder values with your product details. This markup should go in either the <head> or <body> section of the product page HTML.

Once you’ve uploaded this markup to your pages, use Google’s Rich Results Test tool to check that there are no issues.

Alternatively, you can also use Semrush’s Site Audit tool to check for issues. Use this tool if you have a large catalog and don’t want to check each page individually.

To get started, open the tool, set up a project for your site, and run a full audit. Once complete, go to the “Markup” report, and you’ll see a breakdown of which pages have valid markup, which have errors, and which are missing structured data altogether.

4. Your JSON Manifest Is a New SEO Surface

UCP requires merchants to publish a JSON manifest at /.well-known/ucp. This is a file that lists the capabilities your store supports. 

When an AI agent first interacts with your store, it fetches this manifest to understand what your store supports. If the manifest is missing, incomplete, or ambiguous, the agent disregards your site from agentic checkout.

Work with your engineering team to make sure your UCP manifest is published. Even though this is an engineering team's deliverable, SEOs should have visibility over it.

5. Traditional Analytics Will Leave Gaps in Your Reporting

UCP-enabled transactions generate no pageviews, no sessions, and no events on your website. The sale is completed entirely through the agent. Google Analytics sees nothing.

This isn't a hypothetical future problem. If your team's value is measured by traffic and on-site conversions, agentic commerce creates an attribution gap that will only grow.

Google hasn’t shipped dedicated UCP conversion reporting yet, so this is a gap you should start planning for now. Work with your analytics and engineering teams to build the internal infrastructure for capturing server-side order data. 

This means logging order sources at the API level—identifying which transactions were initiated by agents versus direct site visits—and building reporting that surfaces this data alongside your existing analytics. 

When Google releases UCP-specific reporting in Merchant Center (which industry practitioners expect in the near future), you’ll want the internal infrastructure ready to integrate it. 

On the visibility side, Semrush's AI Visibility Toolkit tracks your brand mentions, share of voice, and cited pages across AI platforms like ChatGPT, Google AI Overviews, AI Mode, and Gemini. 

These metrics won’t replace server-side attribution for UCP transactions, but they show whether your brand appears in the AI surfaces where shoppers increasingly start their buying journey. 

6. Ecommerce SEO Gets More Cross-Functional 

As you can probably tell by now, getting your store ready for agentic commerce isn’t one team’s job.

The requirements touch nearly every department in your organization.

For example:

• Return policies (Legal)
• Product identifiers (Engineering)
• Merchant Center configuration (Shopping teams)
• Real-time catalog accuracy (Merchandising)

This means SEO's role is expanding. You’re no longer required to just focus on traditional SEO deliverables, but you also need to coordinate across different teams to make sure your store remains eligible for AI-driven discovery and transactions.

The Era of AI Agents Is Here

AI agents are changing how ecommerce works. 

For the first time, discovery, comparison, and checkout can all happen through an AI agent without the shopper ever visiting your website. 

The businesses that win in this new era will be the ones that treat UCP as a cross-functional priority—not just an SEO initiative, but a coordination effort across engineering, legal, merchandising, and analytics. 

Here’s where to start: 

• Set up or audit your Google Merchant Center account
• Add the native_commerce attribute to eligible products
• Make sure your product data is consistent between your feed and your site
• Publish your /.well-known/ucp manifest so AI agents can discover your capabilities
• Monitor your presence in AI surfaces to make sure you’re appearing where shoppers are looking

At Semrush, we're building tools to help businesses stay visible in the agentic future of the web. The AI Visibility Toolkit helps you understand, measure, and improve your brand’s presence across AI platforms—so you can track whether your products and content show up in the AI surfaces that increasingly drive purchasing decisions. 

Try the AI Visibility Toolkit today.