Two open protocols are about to decide who gets to sell inside AI conversations. If you're running an ecommerce brand, this is the most important thing you can read this month.

OpenAI and Stripe launched the Agentic Commerce Protocol (ACP) to power instant checkout inside ChatGPT. Google, together with Shopify, Stripe, Target, Walmart, and dozens of other industry leaders, launched the Universal Commerce Protocol (UCP) to do the same across Gemini and Google AI Mode.

These aren't competing standards in any adversarial sense. They're complementary layers of a new commerce stack — and brands that support both will have a structural advantage over those that pick one or wait.

What Is ACP?

ACP — the Agentic Commerce Protocol — is an open standard developed by Stripe and OpenAI. It defines how AI agents interact with merchants to complete transactions programmatically.

In practical terms, ACP is what makes instant checkout inside ChatGPT work. When a shopper asks ChatGPT for product recommendations and decides to buy, ACP handles the product feed, the checkout session, and the payment flow — all without the shopper ever leaving the conversation.

How ACP works

Product feeds — Your catalog gets structured in a format ChatGPT can parse: pricing, inventory, attributes, all in real time.
Checkout sessions — When a shopper is ready to buy, ACP creates a secure checkout session with your existing payment processor (typically Stripe).
Order completion — The transaction completes, the order flows into your OMS, and you remain the merchant of record.

The key design principle behind ACP is simplicity. It's built to let merchants sell through AI agents with minimal friction, using infrastructure (like Stripe) that most brands already have.

What Is UCP?

UCP — the Universal Commerce Protocol — is an open standard co-developed by Google, Shopify, Stripe, and a coalition of major retailers and payment providers including Target, Walmart, Macy's, Sephora, PayPal, Visa, Mastercard, and Klarna.

UCP powers instant purchases inside Gemini and Google AI Mode in Search. When a shopper discovers your product through Gemini or AI Mode and wants to buy, UCP handles the entire transaction lifecycle — from checkout session creation to order fulfillment and returns.

How UCP works

Merchant Center feeds — Your existing Google Merchant Center product data becomes the basis for discovery on Google AI surfaces.
UCP Profile — You publish a profile that tells Google about your capabilities, payment handlers, and public keys for signature verification.
Checkout endpoints — UCP defines three core REST endpoints: session creation, session updates, and session completion. Google's AI surfaces call these to execute purchases.
Order sync — After purchase, you push order updates (shipping, delivery, returns) back to Google via webhooks.

What makes UCP distinct is its scope. It's designed to handle the full commerce lifecycle — not just checkout, but identity linking (OAuth 2.0 for account connections), multi-item carts, loyalty programs, and post-purchase experiences like tracking and returns. The protocol is also explicitly interoperable with MCP (Model Context Protocol), A2A (Agent2Agent), and AP2 (Agent Payments Protocol).

The industry coalition behind UCP

UCP isn't just a Google project. The endorsement list reads like a who's-who of commerce: Shopify, Stripe, Target, Walmart, Best Buy, Lowe's, Home Depot, Macy's, Sephora, Ulta, Kroger, Gap, Chewy, Wayfair, Etsy, Zalando, Flipkart, Carrefour, and Shopee on the retail side. Visa, Mastercard, PayPal, Klarna, Affirm, Amex, Adyen, Worldpay, Fiserv, Block, and Splitit on the payments side. Salesforce and Ant International in the platform space.

When this many major players align on a standard, it's not experimental. It's infrastructure.

ACP vs UCP: Key Differences

Both protocols solve the same fundamental problem — enabling purchases inside AI conversations — but they serve different ecosystems.

| | ACP | UCP | |---|---|---| | Developed by | Stripe & OpenAI | Google, Shopify, Stripe & coalition | | Powers checkout in | ChatGPT | Gemini & Google AI Mode | | Payment handling | Stripe-native | Open wallet ecosystem (Google Pay, AP2) | | Product data source | Custom product feeds | Google Merchant Center + custom feeds | | Checkout model | Embedded checkout sessions | Native checkout + optional embedded | | Identity | Session-based | OAuth 2.0 identity linking | | Post-purchase | Basic order flow | Full lifecycle (tracking, returns, refunds) | | Protocol interop | ACP-specific | MCP, A2A, AP2 compatible | | Scope | Checkout-focused | Full commerce lifecycle |

The differences aren't about better or worse. They reflect different design philosophies and different surfaces. ACP optimizes for speed-to-market on ChatGPT. UCP optimizes for breadth and interoperability across Google's ecosystem.

Why Both Matter

Here's the reality most brands haven't internalized yet: AI shopping is not a single-platform game.

ChatGPT has hundreds of millions of users. Gemini is embedded in Google Search, Android, and the broader Google ecosystem — which means billions of touchpoints. If your products can't be purchased inside both, you're leaving revenue on the table.

Consider the parallel to early mobile commerce. The brands that built for both iOS and Android didn't just double their reach. They captured the market while competitors debated which platform to prioritize.

The shopper doesn't care about protocols

From the shopper's perspective, they ask an AI for a product recommendation. They decide to buy. The purchase happens. Whether that happens via ACP in ChatGPT or UCP in Gemini is invisible to them.

What matters is that your brand shows up, your checkout works, and the experience is seamless. If it isn't, the AI recommends a competitor. There's no search results page to scroll through. There's no second chance.

What Wildcard Does With Both Protocols

This is where Wildcard comes in. We implement both ACP and UCP so brands can sell across every major AI surface through a single integration.

Here's what that means in practice:

One product feed integration — We connect to your PIM or ecommerce platform once. Your catalog becomes available to both ChatGPT (via ACP) and Gemini/Google AI Mode (via UCP).
Unified checkout infrastructure — We build the checkout endpoints that both protocols require. Your existing payment processor stays in place.
Merchant of record everywhere — You maintain full control of customer relationships and data, regardless of which AI surface drives the sale.
Single analytics view — Track performance across ChatGPT and Gemini from one dashboard. See which AI surface drives more discovery, which converts better, and where to optimize.

The alternative is building two separate integrations, managing two sets of endpoints, and maintaining two technical relationships. For most ecommerce teams, that's neither practical nor necessary.

What You Should Do Now

1. Understand your current AI visibility

Before implementing either protocol, you need to know where your products stand. Are they being recommended in ChatGPT? In Gemini? Which competitors are winning the AI recommendations in your category?

Wildcard's analytics platform shows you exactly this — rankings, competitor comparisons, and optimization recommendations across both surfaces.

2. Get your product data in order

Both ACP and UCP reward rich, structured product data. If your catalog has incomplete attributes, outdated descriptions, or inconsistent pricing, fix that first. It affects your visibility on both platforms.

If you're already using Google Merchant Center, you have a head start on UCP. Make sure your feeds are complete and up to date.

3. Enable instant checkout

The biggest conversion advantage in AI commerce is removing friction. When a shopper decides to buy inside ChatGPT or Gemini, if they have to leave the conversation to complete the purchase, you've already lost them.

Implementing ACP and UCP checkout is the single highest-ROI move for AI commerce readiness.

4. Think cross-platform from the start

Don't pick one protocol and hope it wins. The landscape is converging, not consolidating. ChatGPT and Gemini will coexist, just like iOS and Android coexist. Build for both from day one.

The Bigger Picture

ACP and UCP represent a fundamental shift in how commerce infrastructure works. For the first time, the checkout experience is being standardized across AI platforms — not by individual retailers, but by open protocols backed by the largest companies in technology and commerce.

This is early. UCP's roadmap includes multi-item carts, loyalty program integration, and expanded post-purchase support. ACP will continue to evolve alongside OpenAI's agent capabilities. Both protocols will get richer and more capable over time.

The brands that adopt early will shape how their categories work in AI commerce. The brands that wait will adapt to rules written by their competitors.

The Bottom Line

Two protocols. Two AI surfaces. One reality: AI commerce is happening now, and the infrastructure layer is being built in the open.

ACP powers ChatGPT. UCP powers Gemini and Google AI Mode. Together, they cover the majority of AI shopping interactions happening today.

The brands that implement both — through a single integration with Wildcard or through direct implementation — will be the brands that capture the next wave of commerce. The rest will be wondering why their products stopped showing up.

If you're ready to get started, book a demo and we'll show you exactly where your products stand across both AI surfaces and how to enable instant checkout through ACP and UCP.