Universal Commerce Protocol (UCP): 7 Things Marketers Need to Know About Google’s New Agentic Commerce Standard

The shopping experience is about to fundamentally change. On January 11, 2026, Google CEO Sundar Pichai announced the Universal Commerce Protocol (UCP) at the National Retail Federation conference. This open standard enables AI agents to browse, compare, negotiate, and complete purchases on behalf of consumers without requiring custom integrations for every retailer.

Here’s what makes this significant: McKinsey projects agentic commerce will reach $3 trillion to $5 trillion globally by 2030. The protocol race is on, with Google, OpenAI, Stripe, and others competing to define how AI-powered shopping will work. If you’re in marketing or e-commerce, this is infrastructure you need to understand.

What’s Covered

1. What UCP actually is and why it matters (Best Insight)
2. The $3 to $5 trillion agentic commerce opportunity
3. Who built UCP and who has endorsed it
4. How UCP works technically
5. UCP vs. OpenAI’s Agentic Commerce Protocol
6. Security, payments, and merchant control
7. What this means for retailers and marketers

1. What UCP Actually Is and Why It Matters (Best Insight)

The Universal Commerce Protocol is an open-source standard that creates a common language for AI agents, retailers, and payment providers to transact together. It covers the entire shopping journey: product discovery, checkout, identity linking, and post-purchase support like order tracking and returns.

Before UCP, building agentic commerce required custom integrations between each AI platform and each retailer. That approach doesn’t scale. As Shopify’s engineering team explains, commerce is too complex and variable for monolithic point-to-point connections. UCP applies the TCP/IP pattern to commerce: layered responsibilities, clear APIs, and composable extensions.

The protocol organizes around three architectural layers:

• Shopping Service: Core transaction primitives including checkout session, line items, totals, messages, and status
• Capabilities: Major functional areas like Checkout, Orders, and Catalog, each independently versioned
• Extensions: Domain-specific schemas added through composition, such as fulfillment options, discounts, and loyalty programs

The practical benefit: implement UCP once and your products become discoverable and purchasable across Google AI Mode, Gemini, and potentially any other AI agent that adopts the standard.

2. The $3 to $5 Trillion Agentic Commerce Opportunity

The market projections for agentic commerce are substantial, and multiple research firms are converging on similar estimates. This isn’t speculative futurism. Consumers are already using AI for product research, and the transition from discovery to transaction is accelerating.

The adoption indicators are already present. According to Adobe’s holiday data, AI-driven traffic to seller sites grew 693% during the 2025 holiday season. Morgan Stanley’s survey found 23% of Americans made a purchase via AI in the past month. Half of US consumers now use AI when searching the internet.

The commercial incentive is clear. Shopping journeys that currently involve multiple tabs, price comparisons, and checkout abandonment will compress into single conversational flows. The protocols that enable this compression will capture significant platform value. Actual attribution will likely undercount early agent-mediated purchases as measurement frameworks catch up to the new channel.

3. Who Built UCP and Who Has Endorsed It

UCP wasn’t built by Google alone. The protocol was co-developed with five major commerce and retail companies and has secured endorsements from over 20 additional partners across payments, retail, and technology.

Co-Developers

Google, Shopify, Walmart, Target, Etsy, and Wayfair worked together to design the protocol. Each brought specific expertise: Google on AI infrastructure and scale, Shopify on checkout complexity across millions of merchants, Walmart and Target on enterprise retail operations, and Etsy and Wayfair on marketplace dynamics.

Shopify’s VP Vanessa Lee stated: “Shopify has a history of building checkouts for millions of unique retail businesses. We have taken everything we’ve seen over the decades to make UCP a robust commerce standard that can scale.”

Endorsements

The endorsement list reads like a directory of major commerce infrastructure:

• Payment Networks: Mastercard, Visa, American Express
• Payment Processors: Stripe, PayPal, Adyen, Worldpay
• Retailers: Best Buy, Home Depot, Macy’s, Kroger, Sephora, Ulta, Gap, Lowe’s, Chewy
• International: Zalando, Flipkart, Carrefour, Shopee, Ant International

Notably, Stripe endorsed UCP despite co-developing the competing Agentic Commerce Protocol with OpenAI. This signals that payment processors see value in supporting multiple standards rather than betting on a single winner.

4. How UCP Works Technically

UCP defines three core capabilities in its initial release: Checkout, Identity Linking, and Order Management. Each capability can operate independently or in combination, and merchants choose which to implement based on their business needs.

Checkout Capability

The checkout capability handles cart management, tax calculations, dynamic pricing, fulfillment options, and payment processing. It uses a state machine model where a checkout progresses through defined statuses: incomplete, ready_for_complete, complete_in_progress, and completed.

A key design decision: checkouts that can’t be completed entirely via API can escalate to human-in-the-loop flows. The protocol includes a requires_escalation status and continue_url field that hands off to a business UI when agent capabilities aren’t sufficient. This typically triggers during high-risk scenarios, such as age-restricted purchases (alcohol, tobacco), when shipping addresses fail AVS (Address Verification Service) checks, or when regulatory constraints require explicit human confirmation.

Identity Linking

Identity linking uses OAuth 2.0 to enable platforms to obtain authorization to perform actions on a user’s behalf. This supports loyalty programs, saved preferences, and repeat purchase flows without exposing credentials.

Order Management

The order capability handles post-purchase lifecycle events through webhooks: shipped, delivered, returned, refunded. This enables AI agents to provide order status updates and manage returns within conversational interfaces.

Transport Options

UCP is transport-agnostic. Businesses can expose capabilities via REST APIs, Model Context Protocol (MCP), or Agent2Agent (A2A) depending on their infrastructure. This flexibility means merchants don’t need to rebuild their stack for each AI platform.

5. UCP vs. OpenAI’s Agentic Commerce Protocol

UCP isn’t the only agentic commerce standard. OpenAI and Stripe launched the Agentic Commerce Protocol (ACP) in September 2025 to power Instant Checkout in ChatGPT. Both are open-source. Both preserve merchant-of-record status. But they differ in scope and ecosystem.

Competitive Surface Map

The practical reality: major retailers are implementing both. Walmart announced Google Gemini integration via UCP at NRF 2026 while already seeing 20% of referral traffic from ChatGPT. Shopify co-developed UCP while also supporting over 1 million merchants on ChatGPT Instant Checkout via ACP.

The strategic calculus is straightforward: users split across AI platforms, so merchants need presence on multiple surfaces. Protocol interoperability reduces the cost of multi-platform distribution.

6. Security, Payments, and Merchant Control

Security is the prerequisite for agentic commerce adoption. UCP addresses this through the Agent Payments Protocol (AP2), which Google developed with input from over 60 organizations including Mastercard, PayPal, Coinbase, and American Express.

AP2 uses cryptographically-signed digital contracts called Mandates to create non-repudiable audit trails from intent to cart to payment. Three mandate types handle different scenarios:

• Intent Mandate: Defines permitted agent behaviors and spending boundaries for delegated tasks
• Cart Mandate: Captures explicit user approval for a specific cart and total
• Payment Mandate: Authorizes the actual payment transaction with cryptographic proof of user consent

Payment information flows through tokenization. The user’s actual payment credentials never pass through the AI agent. Instead, scoped tokens authorize specific merchants for specific amounts, reducing fraud surface and protecting sensitive data.

The merchant control design is explicit in the protocol. Retailers remain merchant of record for all transactions. They retain ownership of customer data, set their own terms and conditions, handle fulfillment and returns, and can reject orders through their existing systems. The AI agent facilitates discovery and checkout but doesn’t intermediate the customer relationship.

7. What This Means for Retailers and Marketers

UCP shifts the competitive landscape for product discovery. If shoppers increasingly discover and purchase through AI conversations, traditional search and browse interfaces become less central. The question becomes: how do your products surface in conversational queries?

Data Quality Becomes Critical

AI agents can only recommend and transact products they can understand. UCP assumes high-quality, machine-readable product feeds with detailed attributes, accurate inventory, and complete metadata. Merchants with poor catalog hygiene will see reduced visibility and failed orders.

Google announced new Merchant Center data attributes specifically for conversational commerce: answers to common product questions, compatible accessories, substitutes, and rich media. These attributes complement traditional keywords with the semantic context AI agents need.

Channel Strategy Expands

Agentic commerce creates a new channel that sits alongside website, app, and marketplace. It requires decisions about where to enable AI checkout, what promotions to offer through agent surfaces, and how to handle the reduced touchpoints between discovery and purchase.

As Crone Consulting CEO Richard Crone noted, merchants face a tradeoff: increased discoverability versus reduced control over the last touchpoint. The product detail page and checkout experience have historically been opportunities for cross-sell and upsell. Agent-mediated checkout compresses that funnel.

Early Movers Have Advantage

Behavior shifts that took over ten years during the desktop-to-mobile transition are happening in 12 to 24 months with AI. Retailers establishing protocol presence in H1 2026 will capture traffic before the holiday rush forces mass adoption. The window for differentiation is narrow.

What Changes in 2026 vs 2024

In 2024, AI shopping assistants were demos and experiments. In 2026, they’re infrastructure with payment rails. The shift from “AI can search for products” to “AI can complete purchases” fundamentally changes the unit economics of customer acquisition. Brands that optimized for click-through are now competing for agent-selection.

What breaks if you ignore this for 12 months: your competitors establish preferred merchant status with AI platforms while you’re still debating strategy. Agent recommendation algorithms develop preferences based on early integration quality. Your product data gaps become visible as competitors with clean feeds capture the agent-mediated demand you could have served.

From a marketing systems perspective, UCP matters less as a Google product and more as the first credible attempt to standardize agent-mediated demand. The protocol itself is less important than what it represents: the formalization of AI agents as a commerce channel with its own infrastructure, measurement, and competitive dynamics.

Frequently Asked Questions

What is the Universal Commerce Protocol?

The Universal Commerce Protocol (UCP) is an open standard developed by Google in collaboration with Shopify, Walmart, Target, and other industry leaders. It creates a common language for AI agents to interact with retailers across the entire shopping journey, from product discovery through checkout and post-purchase support.

How is UCP different from OpenAI’s Agentic Commerce Protocol?

UCP covers the entire commerce lifecycle including discovery, checkout, identity linking, and order management. OpenAI’s Agentic Commerce Protocol (ACP) focuses primarily on the checkout transaction layer. Many retailers, including Walmart and Shopify, are implementing both protocols to reach users across different AI platforms.

Do retailers lose control of customer relationships with UCP?

No. UCP explicitly preserves merchant-of-record status. Retailers retain full ownership of customer data, relationships, and the post-purchase experience. They control pricing, fulfillment, returns, and support. The AI agent acts as a facilitator, not an intermediary that owns the customer relationship.

What payment methods does UCP support?

UCP uses an open payment handler design that supports any payment processor or wallet. Google’s implementation starts with Google Pay and will add PayPal. The underlying AP2 protocol supports pathways for credit and debit cards, real-time bank transfers, and emerging digital asset rails through cryptographically secure tokenized payments.

How large is the agentic commerce opportunity?

McKinsey projects the global agentic commerce market will reach $3 trillion to $5 trillion by 2030, with the US alone representing up to $1 trillion. Morgan Stanley estimates agentic shoppers could capture 10% to 20% of US e-commerce spending by 2030, worth $190 billion to $385 billion.

What retailers and payment companies support UCP?

UCP was co-developed with Google, Shopify, Walmart, Target, Etsy, and Wayfair. It has been endorsed by over 20 additional partners including Mastercard, Visa, American Express, Stripe, PayPal, Best Buy, Home Depot, Macy’s, Kroger, Sephora, and Zalando.