Google says a protocol is needed to address this, as it provides the basis to prove that a user has authorized an agent to make a purchase; to enable a merchant to authenticate that the agent's request reflects the user's intent; and to determine accountability if a fraud or error occurs.

AP2 is designed to be an open, shared protocol that provides a common language for secure, compliant transactions between agents and merchants, helping to prevent a fragmented ecosystem. It also supports different payment types - from credit and debit cards to stablecoins and real-time bank transfers.

The protocol uses mandates - tamper-proof, cryptographically-signed digital contracts that serve as verifiable proof of a user's instructions.

This, according to Google, addresses the two primary ways a user will shop with an agent: real-time purchases where the human is present, and delegated tasks where the person is not present.

Google has also worked with Coinbase, Ethereum Foundation, MetaMask and others on an A2A x402 extension, a production-ready offering specifically for agent-based crypto payments.