What is agentic checkout?

"Agentic checkout" appears in Google's announcements, in OpenAI's documentation and in Shopify's admin, and in each place it describes something a little different. What they have in common is who completes the payment step: an AI agent, on behalf of a person. It is not a new payment gateway or a redesign of your checkout page. It matters to a store because it changes who reads its checkout: the agent shows the shopper the totals, the shipping and the errors the store calculates, so that data has to be exact before anyone presses buy.

How it works

Agentic commerce has three phases: discovering the product, recommending it and buying it. Agentic checkout is the third. OpenAI's documentation for the ACP (Agentic Commerce Protocol) describes it step by step: the assistant collects the buyer's, shipping and payment details, and calls the store to create or update a checkout session. The store validates the order, decides the shipping options, calculates taxes, analyzes risk, charges through its usual provider and accepts or rejects the order. The assistant only reflects what the store answers.⁠^{[1]OpenAI Developers. Key concepts (Agentic Commerce)}

Payment comes with limits. In the ACP, OpenAI prepares a single-use payment request with a maximum amount and an expiry, based on what the person chose, and hands it to the store's payment provider.⁠^{[1]OpenAI Developers. Key concepts (Agentic Commerce)} OpenAI sums it up in three principles: the person confirms each step before anything is done, payment credentials are only valid for a specific amount and merchant, and only the information needed for the order is shared.⁠^{[2]OpenAI. Buy it in ChatGPT: Instant Checkout and the Agentic Commerce Protocol}

With those pieces, two designs are visible today:

• Payment is completed inside the assistant. Google's guide to the UCP (Universal Commerce Protocol) calls this route the checkout path: the whole purchase happens in Google AI Mode or in Gemini, with Google Pay and with order status notifications. The alternative, the cart path, hands the cart to the store's site for the shopper to pay there.⁠^{[3]Google for Developers. UCP on Google: integration guide overview} Instant Checkout in ChatGPT is the first route.⁠^{[1]OpenAI Developers. Key concepts (Agentic Commerce)}
• The agent buys on the store's site. The agentic checkout Google announced on May 20, 2025 for AI Mode works this way: you track a product's price, choose size, color and how much you want to spend, and when the price-drop alert arrives you confirm and tap "buy for me". Google adds the item to the cart on the merchant's site and completes the payment with Google Pay. It was announced for the United States "in the coming months".⁠^{[4]Google, The Keyword (May 20, 2025). Shop with AI Mode, use AI to buy and try clothes on yourself virtually}

A third case remains, buying without the person present. The AP2 (Agent Payments Protocol), which Google introduced on September 16, 2025, solves it with signed mandates: the person signs in advance an intent mandate with their rules (maximum price, timeframe and other conditions), and the agent generates the cart mandate when they are met.⁠^{[5]Google Cloud, official blog. Announcing Agent Payments Protocol (AP2)}

What works today and what is announced

This field changes every few months. What has been published, as of October 6, 2026:

The reading is clear: payment inside the assistant exists, but almost all of it is in the United States, and OpenAI took a step back with its own in March 2026. Outside the United States, none of these pages gives dates.

In a store

A fictional example: a coffee maker store that turns on payment inside an assistant. This is what the agent asks it at each step, according to OpenAI's specification, and what the store has to be able to answer on its own:⁠^{[9]OpenAI Developers. Agentic Checkout Spec}

No row is new for a store: it is its usual cart logic, answered to a machine and not to a web page. What is new is that there is no person looking at your page to notice the error; whatever you answer is what the assistant says.

How to check it

1. If you sell on Shopify, open the Agentic section of the sales channels and see in which channels you have direct payment turned on.⁠^{[8]Shopify Help Center. Agentic storefronts}
2. Check that your store calculates shipping and taxes on its own for a specific address. It is the first thing the agent asks it for.⁠^{[9]OpenAI Developers. Agentic Checkout Spec}
3. For Google, start with Merchant Center: shipping, returns and feed in order, and then choose between payment inside Google or handing the cart to your site. Google approves the integration.⁠^{[3]Google for Developers. UCP on Google: integration guide overview}
4. Ask your payment provider which protocol it supports. Stripe, for example, offers selling through agents with the UCP or with the ACP.⁠^{[10]Stripe, documentation. Agentic commerce}

Related concept: Instant Checkout

Instant Checkout is a brand; agentic checkout is a concept. Instant Checkout is the specific way OpenAI built payment inside ChatGPT, with the ACP and the store charging behind the scenes, and today it is available to approved partners.⁠^{[1]OpenAI Developers. Key concepts (Agentic Commerce)} Agentic checkout includes that and the other designs too: the cart handed to the store's site, the agent that fills in payment there and the purchase with a prior mandate. If you read that agentic checkout has failed because of OpenAI's March 2026 change, that reading is about one implementation, not about the concept.⁠^{[7]OpenAI. Powering Product Discovery in ChatGPT}

To go further, agentic storefronts show how Shopify offers it channel by channel, and the agentic commerce reading path orders the rest of the pieces.