Coinbase-backed x402 V2 links Base, Solana and cards for AI-native payments

Coinbase-backed x402 V2 adds multi-chain routing, wallet sessions and discovery so AI agents and web services can settle HTTP 402 payments across crypto and legacy rails.​

The x402 payments protocol, incubated by Coinbase for autonomous machine-to-machine transactions, released its V2 upgrade on December 11, 2025, according to a company announcement.

Coinbase protocol processes more than 100m API payments across web services

The protocol has processed more than 100 million payments across APIs, AI agents, and web services since its initial deployment six months prior, according to the company. The V2 release incorporates enhancements developed from that deployment period.

The upgrade standardizes network and asset identification, enabling a single payment format to operate across multiple blockchains, including Base and Solana, as well as traditional payment systems such as ACH and card networks, according to the announcement. The design positions x402 as a unified payment layer for cryptocurrency and legacy financial infrastructures.

V2 introduces wallet-based sessions that enable subscription-style access and repeated use of purchased resources without restarting the payment flow, according to the company. The feature is designed to reduce overhead for high-frequency workloads such as large language model inference, automated API calls, and autonomous agent operations by eliminating unnecessary on-chain interactions. Sessions are tied to wallet ownership rather than API keys.

The upgrade establishes a separation between clients, servers, and facilitators, allowing developers to add new blockchains, assets, and payment schemes as isolated modules without modifying the protocol’s foundation, according to the announcement.

A new Discovery extension allows x402-enabled services to expose metadata that facilitators can crawl and index, enabling AI agents to automatically discover services, understand pricing, and initiate payments, the company stated.

Reference software development kits have been rewritten with a plug-in driven architecture based on feedback from early adopters who deployed x402 in production environments, according to the company.

The protocol utilizes the HTTP 402: Payment Required status code as a payment mechanism. Transactions typically settle using stablecoins on Layer 2 networks such as Base, according to the announcement.

The x402 Foundation, established in September 2025, includes Cloudflare, Google, and Visa among its members supporting development of the protocol as an open standard, according to the foundation.