Google Vs. OpenAI: Which AI Is A More Useful Shopping Tool?

AI has been taking on a whole new world of handling tasks and now, shopping is one of them. Agentic AI can do things like suggest what to buy or even completing purchases, now.

OpenAI and Google are certainly taking the lead when it comes to such tech. They’re using two competing systems: OpenAI’s Agent Commerce Protocol (ACP) and Google’s Agent Payments Protocol (AP2). Both were launched in September this year, and though they share a common purpose, they take very different routes to get there.

Tom Hay from PSE Consulting said both systems are open-source and designed to let AI agents buy on behalf of users. He explained that these protocols are more than experiments. They signal a change in how people and merchants might interact in digital commerce.

While both aim to make shopping smoother and more secure, their designs and partnerships show the differences between OpenAI’s quick-to-market method and Google’s larger vision that is more so driven by infrastructure.

How Does OpenAI’s Agent Commerce Protocol Work?

Last week, OpenAI launched ACP in partnership with Stripe and later added Worldpay. Instant Checkout now lets U.S. users buy from Etsy sellers directly within ChatGPT, with over a million Shopify merchants such as Glossier, SKIMS, Spanx and Vuori set to follow.

The system is built to be practical for merchants. It works with their existing setups rather than replacing them. Merchants stay in charge of payments, fulfilment, and customer relationships. OpenAI’s AI agent acts as a digital assistant, securely passing information between users and merchants.

Tom Hay described ACP as a “merchant-centric” model. It runs on existing payment rails and uses Stripe’s Shared Payment Token API to process transactions securely. For users, the process is direct: they confirm orders in the chat, pay with their stored cards, and complete purchases in a few taps. Merchants pay a small fee per sale, while users pay nothing extra.

ACP’s open-source nature means developers can adapt it across systems. OpenAI said the next stage will bring the system to more regions and add multi-item carts, turning ChatGPT into a real shopping assistant that can handle more complex orders.

What Makes Google’s AP2 Different?

Google’s AP2 takes a larger view. Announced with more than 60 collaborators like Mastercard, PayPal, Revolut, American Express and Coinbase, it is made to create a shared standard for agent-led payments across all platforms.

Stavan Parikh and Rao Surapaneni from Google said AP2 works as an extension of existing protocols such as Agent2Agent (A2A) and Model Context Protocol (MCP). Its structure is built to authenticate AI agents and create clear records of user approval. Instead of simply forwarding purchase requests, AP2 uses cryptographically signed “mandates”, which are digital contracts that prove a user authorised a transaction.

There are 2 main types of mandates that exist…

Real-time purchases capture live shopping requests, while delegated tasks allow agents to act later, such as buying concert tickets once they go on sale. These digital trails confirm who approved what, when and how much was spent, creating what Google calls a “non-repudiable audit trail.”

Unlike ACP, which relies on existing payment processors, AP2 supports all payment types… from credit cards to cryptocurrencies. Google has even worked with Coinbase and the Ethereum Foundation to support stablecoin payments through a Web3 extension. This opens the door to both traditional and decentralised finance uses, from consumer shopping to automated business procurement on Google Cloud.

Which System Could Define The Next Phase Of Online Shopping?

OpenAI’s strength lies in its speed as it already has live users buying from merchants in ChatGPT, giving it early data and visibility. Its partnership with Stripe gives it a good positioning in the existing payment world, so adoption is easier for smaller sellers.

Google’s AP2, on the other hand, takes on the heavier technical and regulatory questions. Its design anticipates a time when AI agents handle more autonomous payments, linking to blockchain and smart contract systems. Its alliances across more than 60 organisations also suggest a longer-term attempt to set global standards.

Tom Hay said OpenAI has the “first-mover advantage,” while Google’s system could take longer to mature because it aims for deeper change in how transactions are handled. He added that regulators and payment networks will have to consider new rules around liability, fraud, and transparency as these systems scale.

Both ACP and AP2 represent two ends of the same trend… Turning AI agents from shopping helpers into actual buyers. Whether one becomes dominant or both coexist, the era of agent-led payments is here.