x402 V2 Officially Announced: Major Changes to Make Payments More Flexible

When the x402 protocol was first launched in May of this year under Coinbase’s leadership, it introduced a fundamental idea: reactivating the HTTP 402 status code to embed direct payment logic into network requests. Although the old version handled over 1.1 billion payment transactions in the past six months (including API call fees, on-demand resource purchases for AI agents, and many other applications), it also revealed limitations in cross-chain support, scalability, identity verification, and duplicate payments.

Now, x402 V2 has been released with profound improvements based on real-world issues identified during usage.

No-Repeat Payment: Reusable Sessions Are Key

In the old version, each API call required a complete payment process, causing high latency and costs in high-frequency scenarios. x402 V2 introduces support for wallet identity (such as Sign-In-With-X based on CAIP-122). When users authenticate via wallet and complete the initial payment, the protocol allows creating reusable sessions.

This means subsequent accesses to the same resource can completely skip the on-chain payment process. Users do not need to repeat complex payment procedures each time they use a service within the same session or timeframe, resulting in faster speeds, lower costs, and an experience close to “micro-subscriptions.”

A Single Payment Interface for All Assets

x402 V2 creates a unified payment format, regardless of whether assets are on-chain or off-chain.

Multi-chain support by default: The protocol supports stablecoins and tokens on Base, Solana, and other Layer 2 solutions without requiring custom logic from developers.

Compatibility with traditional payments: Through Facilitators, V2 seamlessly integrates with ACH, SEPA, or card networks.

Dynamic payment routing: Payments can be routed at the request level, transferring funds to specific addresses, roles, or callback logic depending on input content.

What Is Discovery? An Automatic Synchronization Mechanism

x402 V2 introduces the “Discovery” (discovery) extension, allowing public services to expose structured metadata for Facilitators to retrieve. This is an automatic service info synchronization mechanism without manual intervention.

Service prices, routing, and metadata are updated automatically. Facilitators can dynamically index available endpoints without hardcoded directories or manual updates. Sellers only need to publish their API once; the entire ecosystem will synchronize, laying the foundation for a more autonomous internet economy.

Plugin Architecture: Developers Have More Freedom

x402 V2 modularizes the protocol clearly, separating protocol specifications, SDK implementations, and Facilitators. Developers can register new chains, assets, and payment methods as plugins without changing core code.

Configuration is significantly simplified, supporting native Multi-Facilitator setups. The SDK will automatically select the most suitable option based on business priorities (e.g., “Prioritize Solana,” “Avoid Mainnet,” “USDC only”). This greatly reduces “glue code” and helps developers focus on business logic.

AI Agents Become Autonomous “Economic Entities”

The innovations in x402 V2 are revolutionary for AI agents. An AI agent can be equipped with a wallet containing a budget. When it needs to call an API to perform a task or access more powerful computational resources, it can “decide” and complete payments automatically, proactively seeking optimal resources across the network.

Reflecting on What x402 V2 Brings

This upgrade transforms x402 from a simple “pay-per-use” tool into a flexible and universal economic layer. For users, payments are almost invisible, enhancing overall experience. For developers, the more flexible architecture enables rapid development and iteration of complex business models.

However, any technology faces challenges. Realizing x402 V2 requires overcoming barriers such as ecosystem adoption, risks from modules, difficulties in refunds and dispute resolution, and regulatory uncertainties.