Coinbase-powered x402 V2 adds multi-chain routing, wallet sessions, and discovery so AI agents and web services can handle HTTP 402 payments over crypto and legacy rails.
Summary
- x402 V2 standardizes network and asset IDs so that one payment format can span Base, Solana, stablecoin rails, ACH, and card networks.
- New wallet-based sessions enable subscription-like access and repetitive API or AI agent calls without restarting on-chain payment flows.
- Discovery extensions and a plug-in SDK allow facilitators to index x402 services while developers add chains and assets as modular components.
The x402 payment protocol, developed by Coinbase for autonomous machine-to-machine transactions, released its V2 upgrade on December 11, 2025, according to a company announcement.
The Coinbase protocol processes more than 100 million API payments via web services
According to the company, the protocol has processed more than 100 million payments across APIs, AI agents and web services since its initial deployment six months earlier. The V2 release includes improvements developed from that implementation period.
The upgrade standardizes network and asset identification, allowing a single payment format to work across multiple blockchains, including Base and Solana, as well as traditional payment systems such as ACH and card networks, the announcement said. The design positions x402 as a unified payment layer for cryptocurrency and legacy financial infrastructures.
V2 introduces wallet-based sessions which the company says allows subscription-style access and repeat use of purchased resources without restarting the payment flow. 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 interactions in the chain. 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 changing the basis of the protocol, the announcement said.
A new Discovery extension will allow x402 services to expose metadata that facilitators can crawl and index, allowing AI agents to automatically discover services, understand pricing and initiate payments, the company said.
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 uses the status code HTTP 402: Payment required as a payment mechanism. According to the announcement, transactions are typically settled using stablecoins on Layer 2 networks such as Base.
Founded in September 2025, the x402 Foundation includes Cloudflare, Google and Visa among its members who support the development of the protocol as an open standard, the foundation said.
