x402 V2 version is here. What are the major upgrades in the new protocol?

Summary: Felix, PANews

The recently popular x402 protocol has made new progress. Developed by Coinbase and designed specifically for AI agents, the open-source payment protocol x402 launched version 2 (V2) on December 11. This version optimizes the previous V1, expanding from a single payment call to a unified internet payment layer.

x402 was initially released in May 2025, with the idea of embedding payments directly into HTTP using the long-idle 402 status code. Within just a few months, x402 handled over 100 million payments from APIs, applications, and AI agents, supporting various use cases ranging from paid API calls to autonomous agents on-demand purchasing computing resources and data.

Coinbase stated that this update restructured the protocol to make it more universal, flexible, and easier to extend across different networks, transmission methods, identity models, and payment types. It marks a shift from “what the protocol can do” to “how to seamlessly integrate with existing services.”

Unified Payment Interface

x402 V2 introduces a standardized payment interface connecting blockchain networks with traditional payment systems. It supports multiple blockchains including Base and Solana, while maintaining compatibility with ACH and card networks.

By creating a single format to identify networks and assets, x402 V2 simplifies developer integration. Developers can build cross-chain payment flows without complex adjustments or custom logic. This unified architecture supports flexible payment modes, including subscriptions, prepayments, and multi-step billing.

This update also introduces a dynamic “payTo” routing feature, which directs funds to specified addresses, roles, or callback-based payment logic based on requests. This feature is well-suited for marketplace platforms and multi-tenant APIs. Additionally, it enables dynamic pricing based on input data.

Scalable Architecture and Compatibility

The V2 version adopts a modular architecture that separates protocol standards, SDK implementations, and payment service providers. This structure makes x402 V2 plugin-driven, allowing developers to add new blockchains or payment behaviors without modifying the core protocol.

x402 V2 integrates lifecycle hooks that enable builders to insert custom logic at critical points in the payment process (such as before/after payment sending, before/after settlement validation). These hooks support complex functionalities like conditional routing, fault recovery, and metrics monitoring. This approach enhances efficiency and reliability across various financial environments.

The updated SDK supports multiple payment service providers simultaneously, with developers able to prioritize networks or assets according to preference. This flexibility ensures smoother cross-blockchain and platform payment routing. In a unified framework, x402 V2 boosts interoperability, stability, and developer productivity.

Wallet Access and Developer Experience

x402 V2 also overhauls wallet and identity management. By introducing reusable wallet sessions, it eliminates repeated payment verification for returning users or AI agents. This reduces transaction latency and improves cost efficiency in high-frequency payment environments.

The system includes a modular paywall component supporting custom backends for EVM and Solana networks. This modular design encourages developers to build and adjust paywalls to suit different business models. It also lays the groundwork for future wallet-based identity standards (such as “Login with X”).

The x402 V2 update automates service discovery and metadata management through its Discovery extension. This enables service providers to index services, update prices, and manage routes automatically, without manual intervention.

Coinbase stated that the launch of x402 protocol V2 marks another significant milestone in making value flow on the internet as easily as information. By expanding compatibility, simplifying developer experience, and supporting new payment and identity models, V2 transforms x402 into a more flexible payment layer that accommodates manual, application, and agent-driven payments.

Related: Why is x402 a key protocol for enabling crypto payments?