Coinbase has introduced a groundbreaking open-source protocol named x402, designed to revolutionize on-chain payments via HTTP. This innovative system repurposes the HTTP 402 “Payment Required” status code to facilitate direct machine-native payments using stablecoins, offering a seamless and efficient payment solution.
The x402 protocol allows autonomous agents and applications to make payments for API access, data, and services without the need for human intervention, subscriptions, or traditional payment infrastructures. By issuing an HTTP 402 response with payment instructions, servers can prompt clients to initiate on-chain transactions and retry requests with signed payments, enabling microtransactions for content access, context retrieval, and AI inference.
This cutting-edge architecture makes per-use monetization technically feasible and economically viable, with x402 currently available as an open standard with a reference implementation on Coinbase’s GitHub and developer site. The exchange plans to involve the community in future iterations, opening the roadmap for decentralized governance and contributions.
The x402 protocol supports frictionless micropayments across various sectors, enabling AI agents to pay for API access per call, monetize content per article or stream, and sell cloud computing resources on a per-second or gigabyte basis. Real-world use cases include per-play gaming models, per-inference AI services, and per-article paywalls for publishers.
This protocol aims to simplify compliance and operational burdens by eliminating the need for PCI certification and exposure to chargebacks. Once confirmed on-chain, all transactions are final, and payment processing becomes entirely decentralized.
x402 addresses inefficiencies in existing payment systems by offering low-latency, irreversible payments with settlement times averaging 200 milliseconds when deployed on rollups. The protocol executes payments using stablecoins, with a chain-agnostic design that supports multiple blockchains and tokens, facilitating real-time revenue collection through client-server communication.
Developers can easily integrate the x402 protocol using a JSON payment request format embedded in the HTTP 402 response. Clients respond by signing a payment authorization using the EIP-712 standard, ensuring secure and efficient transactions. Coinbase provides middleware libraries for Node.js and browser environments, simplifying integration with one line of code and offering transparency into transaction details.
Overall, x402 proposes a foundational change in how internet services interact with money by providing on-chain payments via HTTP, offering a seamless and innovative solution for modern payment needs.