On Tuesday, Google announced a new open protocol for purchases initiated by AI agents — automated software programs that can shop and make decisions on behalf of users — with backing from more than 60 merchants and financial institutions. Called the Agent Payments Protocol (AP2), the system is meant to be interoperable between AI platforms, payment systems and vendors, providing a traceable paper trail for each transaction.

In a post announcing the protocol, Google executives emphasized their commitment to openness. “We are committed to evolving this protocol in an open, collaborative process, including through standards bodies, and  invite the entire payments and technology community to build this future with us,” wrote Stavan Parikh and Rao Surapaneni, who are VPs at Google and Google Cloud, respectively.

The full specification for AP2 was posted to GitHub in conjunction with the announcement.

The protocol is built for a future in which AI agents routinely shop for products on customers’ behalf, and engage in complex real-time interactions with retailers’ AI agents. One example in Google’s post imagines a chatbot user asking their agent to shop for a bike trip, which triggers a spontaneous time-sensitive bundle offer from a bike shop’s agent.

In another example, a user asks for travel and lodging for a weekend vacation, giving only the dates, location and budget. “The agent can then interact with both airline and hotel agents, as well as online travel agencies and booking platforms,” the post explains, “and once it finds a combination that fits the budget, it can execute both cryptographically-signed bookings simultaneously.”

Enabling that kind of transaction is complex, from both a technological and social standpoint. AP2 requires agents to register two separate approvals before a purchase can be made: first the “intent mandate” (essentially telling the AI, “I’m looking for a polka dot neck tie”), which enables the agent to search for a specific item and negotiate with sellers; then the “cart mandate,” which gives final approval for a purchase once a specific item has been found.

The protocol also contains a provision for fully automated purchases, in which the agent is permitted to automatically generate a cart mandate once an item is found. Those circumstances require a more detailed intent mandate, specifying price limits, timing, and other rules of engagement. In either case, the goal is to maintain an auditable trail that can be re-examined in cases of fraud.

In collaboration with cryptocurrency outfits Coinbase, Metamask and the Ethereum foundation, Google also produced an extension that would integrate the cryptocurrency-oriented x402 protocol, allowing for AI-driven purchasing from crypto wallets.

A number of other tech companies are working on their own agentic purchasing systems — most notably Perplexity, which allows for a Buy With Pro service in its agentic browser. The payment provider Stripe also produces software tools for agentic purchasing on its platform, though they are not as comprehensive as AP2.

Like any protocol, the impact of AP2 will depend on its support from other players in the ecosystem — most notably, developers building agentic purchasing systems. But AP2 has already won the support of major financial providers like Mastercard, American Express and PayPal, giving the protocol a significant immediate footprint.