Blog · Published · Updated
UCP (Universal Commerce Protocol): what it is and when it applies to a store in the EU
Short answer
UCP, the Universal Commerce Protocol, is an open standard from Google and Shopify through which an AI agent finds a store's products, builds a basket and runs the purchase. According to Google, buying through UCP in AI Mode and Gemini today covers eligible products in the US, Canada and Australia, for selected merchants. A store in the EU prepares its product data and measurement now.
How we workDetails ↓
- 01Call30 minutes with an engineer, free
- 02PrototypeA working system on your process and data, free
- 03ImplementationTarget and fixed price in the contract; 50% at signing
- 04Acceptance50% once the agreed target is met
- net for the automation of one process, paid once
- from €3,000
- from signing the contract to acceptance
- 2–6 weeks
- free prototype on your cases
- €0
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Author: Syntalith · 3 min read
Statistics
Purchases by AI agents: statistics 2026
3 countries
covered by UCP purchases in AI Mode and Gemini according to Google: the United States, Canada and Australia, for selected merchants. The EU is outside that scope.
seller of record
According to Google (2026), a merchant selling through UCP remains the seller of record, and the protocol is compatible with A2A, AP2 and MCP.
8
According to the A2A Protocol project (2026), version 1.0 of A2A was released on 12 March 2026, and the standard is led by a technical committee with representatives of 8 technology companies.
78%
According to Eurostat (2025), 78% of internet users in the EU bought or ordered goods or services online in the previous 12 months.
Source: Eurostat, e-commerce statistics for individuals (2025) ↗
Figures checked: 22 October 2026
How UCP works
The store publishes a profile in a JSON file at /.well-known/ucp. The profile describes the store's features, for example checkout, discounts and delivery, and the payment methods it supports. The agent fetches the profile, compares it with its own capabilities and uses the part they share (Google Developers Blog).
| Element | What it means for the store |
|---|---|
| Features | the store chooses what to offer: checkout, discounts, delivery, orders |
| Extensions | its own features, for example a loyalty programme, in the namespace of the store's domain |
| Transport | a REST API, MCP or A2A, depending on the store's technology |
| Payments | the store names the providers, and the agent picks one |
| Handover to a person | the buyer finishes the purchase in an embedded checkout |
Shopify Engineering describes how, when a merchant requires something the agent cannot do, the agent fills in what it can and the buyer completes the rest in an embedded checkout.
How UCP differs from ACP and WebMCP
UCP is the Google and Shopify standard for purchases in AI Mode and Gemini. ACP is developed by OpenAI with Stripe, and since March 2026 it has mainly carried product feeds into ChatGPT. WebMCP in Shopify is a set of checkout tools for agents that run in the buyer's browser. All three use the same product data from the store, so work on variants, units and availability pays off in every channel. They differ in who runs the purchase and where the payment happens: with UCP in Google the payment goes through Google Pay, and with WebMCP it goes through the store's checkout with the buyer's confirmation.
What the merchant keeps
Merchant Center Help says the merchant remains the seller of record and can adapt the integration to its checkout requirements. The buyer pays through Google Pay with payment methods and an address from Google Wallet. The buy button appears only on products with the native_commerce attribute, and taking part requires an application to the early access programme. According to Google, UCP is compatible with A2A, AP2 and MCP.
- 01Profile/.well-known/ucp with features and payments
- 02Discoverythe agent finds the product in the store's data
- 03Basketvariant, quantity and delivery according to the profile
- 04PaymentGoogle Pay with details from Google Wallet
- 05Orderthe merchant as the party to the transaction
What a store in the EU can do now
- A complete Merchant Center feed with variants and availability
- Prices, delivery and returns in the page text, readable without images
- Unambiguous variants and units of sale
- Measurement of visits and sales from AI assistants
- Agent requests labelled in your logs once they appear in your country
You can recognise requests from Google by the UCP-Agent header and a User-Agent that starts with „Google/UCP”, so it is worth labelling them in your logs and reports from the start. Shopify co-created UCP and offers it to merchants in its Agentic Storefronts channel (Shopify). A general description of purchases by agents is published by Shopify, and technical questions are answered in Google's UCP FAQ.
A store on Shopify
Agentic Storefronts settings and the quality of product data
configuration
A store on another platform, selling in the EU
a Merchant Center feed, data on the page and measurement
audit from €600
A store with its own system, selling to the US, Canada or Australia
a UCP profile and a checkout integration
from €3,000
A comparison of UCP with ACP, MCP, A2A and AP2 is in AI agent protocols compared, and the plan for a store in agentic commerce. Status checked on 22 October 2026. For the free analysis, bring your store's address and the countries you sell to.
Worked example · Scenario
How we count the payback: an online store
We run the same count for your store in the free analysis.
€2,792
a month for handling 800 orders that bypass the checkout
Payback: 1.3 mo.
6 minutes to retype an order or answer a question and checking in 15% of the old time are our assumptions. €34.90 an hour is the EU average hourly labour cost for 2025 according to Eurostat, for companies with 10 or more employees. Model cost: reading the order in our system (about €0.0006) plus matching the lines (Claude Sonnet 5.5, about 3,000 + 500 tokens), at the ECB rate of 1.1205 USD per euro on 22 October 2026.
See the full calculation →
