Agentic Commerce: UCP vs ACP and What Shopify Stores Can Do Now

UCP and ACP are both shared standards for connecting AI agents to online stores. UCP (Universal Commerce Protocol) was built by Google with Shopify and others, and covers everything from product search to order management. ACP (Agentic Commerce Protocol) was built by OpenAI and Stripe, and covers how product data and payment credentials pass between ChatGPT and a store.

Agentic commerce is the kind of shopping these standards make possible: an AI finds products for a shopper and carries the purchase through. In September 2026, Shopify’s CEO announced on X that shoppers would be able to buy from Shopify stores with Shop Pay inside Muse, Meta’s AI agent.

This article is for people running a store on Shopify or another platform. It covers:

• How UCP and ACP differ (and where AP2 and MCP fit)
• How an order goes through inside an AI
• Where ChatGPT, Google, Meta and Copilot stand, and which stores qualify
• What to set up now
• Common misconceptions

Everything here is checked against official pages from Google, OpenAI, Shopify, Stripe and Microsoft as of October 2026. The rules change month to month, and we’ll update this page when they do.

What is agentic commerce?

Agentic commerce is shopping where an AI agent finds, compares and buys products on the shopper’s behalf. Of the usual steps (search, browse several sites, add to cart, check out), the AI takes over the ones in the middle.

For a store, what changes is where shoppers first meet your products. Until now, you could count on search results and ads to bring people to your site. With agentic commerce, your products get recommended inside an AI’s answer, and sometimes the purchase finishes without the shopper ever leaving the AI.

Shopify’s answer to this is agentic storefronts. Its help center describes it like this:

Shopify’s agentic storefronts lets customers discover and purchase your products in AI channels, such as ChatGPT, Google AI Mode and Gemini, Microsoft Copilot, and Meta.

It’s active by default for eligible stores, and you choose which AI channels to sell on under Sales channels > Agentic in your Shopify admin. Orders go into your admin like any other order, with the channel or referrer shown.

UCP vs ACP

UCP is Google’s broad standard covering search through order management; ACP is the standard OpenAI and Stripe built for buying in ChatGPT. Both keep the store as the seller of record. The main differences:

(Sources: Google Developers Blog, ucp.dev, agenticcommerce.dev, OpenAI, Google Merchant Center Help, ChatGPT for merchants. Checked October 2026.)

It’s easier to think of them as different standards for different entry points than as rivals. Stripe’s docs list “UCP or ACP” as the protocols for selling through agents, and Stripe also sits on UCP’s Tech Council.

Where AP2 and MCP fit

AP2 and MCP often come up in the same news stories as UCP and ACP. Here’s what each one covers:

UCP is designed to work with AP2, A2A (a standard for agent-to-agent communication) and MCP. Shopify’s agent tooling implements UCP over MCP.

How an order goes through inside an AI

Buying inside an AI breaks into four handoffs: product data, checkout, payment and order updates. UCP and ACP define the format of those handoffs. Under both, the store stays the merchant of record; the AI company doesn’t buy and resell your products.

1. Product data: your product information (title, description, price, inventory, images, shipping terms) goes to the AI. Under ACP, the merchant sends a CSV or JSON product feed on a schedule. Shopify stores’ products reach the AI channels through Shopify Catalog.
2. Checkout: when the shopper decides to buy, the AI asks your store’s API to create a checkout. Your side checks inventory, calculates shipping and tax, screens for fraud, and decides whether to accept the order.
3. Payment handoff: the AI doesn’t pass the shopper’s card number to you; it passes a token. Under ACP, Stripe’s Shared Payment Token was the first implementation, and each token is limited to a maximum amount and an expiry. Under UCP, a “payment handler” for each payment method defines how it’s tokenized and handed over. It can also be combined with AP2’s signed records.
4. Order updates: your store tells the AI about order status: shipped, delivered, returned, refunded. UCP defines webhooks for order status changes.

How much work this is depends on whether you build it or your platform does. Shopify handles it behind agentic storefronts, so Shopify stores don’t need to implement either standard. A custom-built store that wants to sell in Google AI Mode has to implement UCP following Google’s developer guide first.

ChatGPT, Google, Meta and Copilot: where things stand

“You can buy it in AI” means different things depending on the channel, because the purchase finishes in different places. Shopify’s help center treats ChatGPT as a discovery channel that sends shoppers to your store. Google, Microsoft and Meta support direct checkout, where the purchase finishes in Shopify-powered checkout inside the AI.

In table form:

Across all channels, your products need to be eligible for Shopify Catalog and you need to accept the Shopify Agentic Storefronts Supplemental Terms of Service. The ChatGPT page also requires a terms of service, privacy policy and return and refund policy set up in your admin.

For Copilot Checkout, Microsoft lists PayPal, Shopify and Stripe as its payment partners. Shopify merchants are enrolled automatically, with controls in the Shopify admin.

ChatGPT moved away from standalone Instant Checkout

Buying in ChatGPT started on September 29, 2025 as Instant Checkout, which let shoppers pay without leaving ChatGPT. ACP was released as the standard behind it. Many explainers still assume that’s how it works.

As of October 2026, OpenAI’s merchant page says:

We’re moving away from a standalone Instant Checkout experience in ChatGPT.

Purchases are instead completed on merchants’ own sites or apps. OpenAI’s developer docs still describe Instant Checkout for approved partners. The same merchant page says ChatGPT shopping is live for US users and that merchants selling through Shopify or Etsy already have their catalogs integrated.

For Shopify stores, shoppers who find your products in ChatGPT move to your own checkout. Shopify’s help center says there’s no setting to turn ChatGPT direct checkout on or off. From the store’s side, ChatGPT isn’t where the purchase happens; it’s where shoppers find your products and get sent to your store.

Muse is now in Japan too, and supports Shop Pay

Muse is a personal AI agent Meta launched on September 8, 2026. It runs as its own app and inside WhatsApp, and launched in the US first. Meta announced it started offering Muse in Japan on October 23, 2026. Shopify’s help center says Shop Pay can display as a wallet or checkout option in Muse, and you don’t need to turn on Shop Pay separately for it.

On the merchant side, you need to sell to customers in the US, Canada, Mexico, Brazil, Japan or Singapore. When we checked Shopify’s help center on October 29, 2026, Japan was on the list (earlier it was the US, Canada and Mexico only).

Which stores can sell through AI channels today

As of October 29, 2026, whether you can sell depends on where your buyers are. Here’s how the requirements above play out:

The row to watch is the second one. For ChatGPT and Meta, the requirement is where your buyers are, not where your store is. Agentic storefronts are on by default for eligible stores, so if you sell internationally into the US, AI channels may already be recommending and selling your products without you having changed anything.

Google said on May 20, 2026 that UCP-powered buying will expand to Canada and Australia in the coming months, then to the UK, and Merchant Center onboarding for Canada and Australia is planned for next year. No other countries have been announced. We don’t speculate on dates here; we’ll update the tables when announcements come.

What Shopify stores can do now

If you sell to US buyers, these channels are likely already live for you, so the first job is to check what’s on. If you don’t, there’s nothing you have to change today, and the work is getting ready so you can sell as soon as you qualify. None of this is only for AI channels: it also helps Google Shopping listings and AI search.

1. Check your agentic settings in Shopify

In your Shopify admin, go to Sales channels > Agentic and see which AI channels are active. If you sell to buyers in the covered countries (Japan included, for Meta), some may already be on. Also check the channel shown on recent orders to see whether any AI channel orders have come in.

2. Fill in your three policies

Shopify’s help center lists a terms of service, privacy policy and return and refund policy as requirements for selling on ChatGPT. Go to Settings > Policies and check that none are blank. Spell out the return window, method and who pays return shipping: AI assistants draw on this when shoppers ask questions.

3. Know which products direct checkout can’t sell

Shopify’s help center says subscriptions, product bundles, customizable products and B2B-only products aren’t supported in Google’s or Meta’s direct checkout. If those are your core products, assume AI shoppers will be sent to your store to buy rather than buying inside the AI. Shopify’s ChatGPT page also says to put any legally required disclosures in the first 6,000 characters of each product description.

4. Clean up product data in Merchant Center and Shopify Catalog

Product information reaches AI channels through Shopify Catalog or Google Merchant Center. Selling in Google AI Mode and Gemini requires a valid Merchant Center account, and product discovery there is powered by Merchant Center. Keeping titles, descriptions, product categories and inventory accurate also improves your Merchant Center feed quality.

5. Decide how you’ll track AI orders

For direct checkout in Google AI Mode and Gemini, Shopify’s help center says:

Google Analytics and custom pixels won’t fire in Google AI Mode and Gemini’s direct checkout.

Only server-to-server pixels (checkout started and completed) fire. The Meta page says the same, and adds that third-party analytics pixels don’t fire on direct checkouts completed on a Meta surface. Orders placed inside the AI don’t reach GA4 as purchases.

The orders themselves land in your Shopify admin, labeled with the channel. The practical move is to agree internally, before the volume grows, that AI channel revenue gets reported from Shopify orders, not GA4. If you judge ad ROAS from GA4 purchases, make sure everyone knows that orders placed inside an AI won’t be credited to any ad.

ChatGPT sends shoppers to your own checkout, so your GA4 tag fires as usual. For how to find ChatGPT traffic in GA4 and reconcile AI orders with Shopify, see GA4 AI Assistant Channel.

If you want orders placed inside an AI in GA4 too, they have to be sent from a server. We built a Shopify app, GapFill, that recovers missing GA4 purchase events server-side. It’s our own product, so read with that in mind. It works alongside your existing tags, the missing purchases report is free, and agentic checkouts can be sent with a source and medium based on the sales channel.

6. Not on Shopify? Know where to apply

If you run a custom-built store or another platform, each AI company has its own route. Google’s is selective: you implement UCP following the developer guide, submit an interest form, and if Google selects you, you get a sandbox in Merchant Center to test. As of October 2026, it’s rolling out gradually in the US, with Canada and Australia to follow next year. For ChatGPT, you apply to share product data through OpenAI’s merchant page (chatgpt.com/merchants), and applicants go on a waitlist.

In January 2026, Shopify also announced an Agentic plan that, per its news post, opens Shopify Catalog to brands whose online store isn’t on Shopify. Per Shopify’s help center, you keep your existing online store, and direct checkout is off by default on that plan.

Common misconceptions

Agentic commerce comes with a lot of new terms, and standards often get mixed up with individual companies’ features. Six we see often:

You have to choose between UCP and ACP

Not on Shopify: Shopify handles both behind agentic storefronts. If you wire up payments yourself, Stripe supports “UCP or ACP.” Only when you build it yourself do you choose, working back from the entry point you want (Google or ChatGPT).

UCP is only for Google’s AI

Google leads UCP, but it was co-developed with Shopify, and Shopify’s agent tooling implements it. Microsoft Advertising also says Microsoft Merchant Center will support UCP (as a future plan, adding richer signals on top of product feeds). Copilot Checkout’s payment partners are PayPal, Shopify and Stripe.

Shoppers pay inside ChatGPT

That was true at launch in September 2025. As of October 2026, OpenAI says it’s moving away from a standalone Instant Checkout experience. For Shopify stores selling on ChatGPT, the purchase finishes in your own checkout.

Any Shopify store can sell through AI worldwide

As of October 29, 2026, Meta is the only channel that covers buyers in Japan. Google covers the US, Canada and Australia, and ChatGPT and Copilot the US.

If people buy inside AI, you won’t need your own site

ChatGPT sends shoppers to your checkout, and even on channels where shoppers can buy inside the AI, we expect many to visit your site to double-check before buying. That only helps if prices, inventory and return terms match between your site and the data you give the AI.

Supporting MCP lets AI shop on your store

MCP is a general way to connect AI to external tools and data. On its own, it doesn’t define payments or order handling. UCP and ACP define checkout and payment handoff, and MCP is one transport they can use.

Fact vs speculation

Coverage of agentic commerce often mixes facts with predictions. Here’s how confident we are in each claim on this page:

Sources

• Under the Hood: Universal Commerce Protocol (UCP) (Google Developers Blog, January 11, 2026)
• How we’re helping retailers thrive with new Universal Commerce Protocol features and AI tools on Google (Google, May 20, 2026)
• How to onboard to the UCP integration hub in Merchant Center (Google Merchant Center Help)
• About the Universal Commerce Protocol (UCP) and UCP-powered checkout feature on Google (Google Merchant Center Help)
• Announcing Agent Payments Protocol (AP2) (Google Cloud Blog, September 16, 2025)
• Universal Commerce Protocol (ucp.dev)
• Agentic Commerce Protocol (agenticcommerce.dev)
• Buy it in ChatGPT (OpenAI, September 29, 2025)
• ChatGPT for merchants (OpenAI)
• Agentic Commerce: Key concepts (OpenAI Developers)
• Agentic commerce (Stripe Docs)
• Universal Commerce Protocol (Stripe Docs)
• Agentic commerce (Microsoft Advertising)
• AI commerce at scale (Shopify, January 11, 2026)
• Agents (Shopify.dev)
• Shopify agentic storefronts (Shopify Help Center)
• Selling on ChatGPT (Shopify Help Center)
• Selling on Google AI Mode and Gemini (Shopify Help Center)
• Selling on Meta (Shopify Help Center)

The Muse partnership was announced in a post on X by Tobi Lütke (Shopify CEO). Muse’s launch date and availability come from press coverage including PBS NewsHour (September 2026). For how Shopify’s ChatGPT integration changed in March 2026, we referred to Digital Commerce 360 (March 17, 2026).