Google releases AI agent payment protocol supported by Coinbase and Ethereum, enabling stablecoin payments

2025-09-17 22:38:47

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Ethereum: "Ethereum makes AI more trustworthy, while AI makes Ethereum more useful. The more smart agents trade, the more a neutral base layer is needed to handle it."

Author: Chloe, ChainCatcher

On September 16, 2025, Google officially launched an open-source payment protocol called Agent Payments Protocol (AP2), designed specifically for transactions between AI agents. This protocol was co-developed by Google in collaboration with over 60 leading global payment and technology companies, including industry giants such as American Express, Mastercard, EigenDA, Mysten Labs, Mesh, BVNK, Crossmint, PayPal, Coinbase, Ethereum Foundation, Adyen, and others. The launch of the AP2 protocol marks a new development phase for AI-driven commerce and payments, allowing users to let AI agents handle various secure transactions.

The AP2 protocol extends Google's previously released Agent2Agent (A2A) protocol and Model Context Protocol (MCP), aiming to address the fundamental limitations of current payment systems that assume human direct interaction with a "buy" button. This open protocol provides a universal "language" that enables AI agents, merchants, and payment service providers to establish a secure and compliant transaction framework across platforms.

Addressing the Fundamental Challenges of AI Agent Payments

The core innovation of the AP2 protocol lies in addressing three fundamental issues in AI agent payments: Authorization, Authenticity, and Accountability. Traditional payment systems are built on the assumption of human direct operation, but the rise of AI agents has completely shattered this premise.

The protocol employs a "Mandates" mechanism to establish trust, which consists of tamper-proof, encrypted digital contracts. These mandates are signed by verifiable credentials (VC) and serve as the foundational evidence for each transaction.

The entire system supports two core transaction modes:

The first is the instant purchase mode, where users first sign an "intention mandate" expressing their purchasing needs, such as "Help me find a black coat." This request is recorded in the initial "intention mandate." Once the AI agent adds the item to the shopping cart, the user will sign a "cart authorization" to complete the transaction.

Signing the cart authorization allows the AI agent to create secure, immutable records of the items and prices, ensuring that users are fully informed.

The second is the delegated task mode, which requires no human assistance. Users will pre-sign a detailed intention mandate, setting parameters such as price limits and time conditions, allowing the AI agent to automatically execute purchases when conditions are met.

Mastercard's Chief Digital Officer Pablo Fourez emphasized, "With the rise of AI-driven commerce, trust and accountability are more important than ever. We are committed to working with Google and other industry leaders to help shape the future of AI agent commerce."

Comprehensive Support for Stablecoins and Cryptocurrency Ecosystem

The groundbreaking design of the AP2 protocol supports various payment methods, from traditional credit and debit cards to stablecoins and instant bank transfers. To accelerate the integration with the cryptocurrency ecosystem, Google has partnered with Coinbase, Ethereum Foundation, and MetaMask to launch a dedicated A2A x402 extension protocol. This is a solution specifically designed for AI agent cryptocurrency payments, allowing AI agents to conduct secure, decentralized payment transactions via blockchain.

Erik Reppel, Head of Developer Platform Engineering at Coinbase, stated, "Integrating x402 into AP2 to support stablecoin payments creates an ideal environment for AI agents to start transacting with each other and testing cryptocurrency payment pathways. It's exciting to see the concept of AI agents paying each other resonate within the broader AI community."

Ethereum Foundation Recently Announced the Formation of an AI Team

Before the launch of the AP2 protocol, the Ethereum Foundation announced the establishment of a new AI-focused team called the "dAI Team" (Decentralized AI Team), led by research scientist Davide Crapis, aimed at promoting the deep integration of AI and blockchain technology.

Davide Crapis, head of the newly announced AI team at the Ethereum Foundation, told Decrypt, "ERC-8004 will support multiple payment methods, but the x402 extension helps enhance the developer experience. In addition to ERC, x402 is also being widely adopted, so this extension opens a new pathway for AI agents built on cryptocurrency tracks."

The core mission of the dAI team is to finalize the development of the ERC-8004 standard, focusing on empowering AI intelligent agents and robots to make payments, collaborate, and adhere to rules without intermediaries. Another aspect is the Decentralized AI Stack, which aims to ensure that the future of AI technology does not rely on a few tech giants but is built on open, verifiable, and censorship-resistant infrastructure.

The standard will be officially released in November at the Devconnect conference, providing a complete technical framework for identity verification, reputation building, and secure interactions for AI agents on the Ethereum network.

Crapis pointed out, "Ethereum makes AI more trustworthy, and AI makes Ethereum more useful. The more intelligent agents transact, the more a neutral foundational layer is needed to handle it."

Prakhar Mehrotra, Global AI Lead at PayPal, expressed, "AP2 provides the foundation for trusted AI agent payments, and PayPal fully aligns with this vision. We are excited to leverage our business expertise to help extend these principles throughout the purchasing process."

Finally, the Ethereum Foundation is not the first to explore the intersection of AI and blockchain. The infrastructure protocol Planck launched a layer-0 blockchain designed for AI in July, while Kite AI introduced an AI-focused Layer-1 blockchain on Avalanche in February.

The trend of crypto projects moving towards AI agents has surged in the market since 2023. These agents can complete financial transactions and other tasks with minimal human oversight.

When asked if he believes the Ethereum Foundation is falling behind in the AI race, Crapis stated that this is not the case. He told Cointelegraph, "The timing feels just right because various project parties have been experimenting with AI on these protocols for about two years."

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