x402 V2 arrives after months of production traffic from APIs, apps, and autonomous agents. The update keeps the core mission the same: move value across the internet as seamlessly as information, whether the actor is a human, an app, or an agent.
Why a V2 now
Real-world usage surfaced areas to tighten the spec, reduce redundancy, and make the protocol easier to extend without forks. V2 cleans up the data model, formalizes extensions, moves payment data to HTTP headers, and ships a rebuilt, modular SDK under the @x402 namespace.
What changes for builders
- Unified payment interface across chains and legacy rails with CAIP-style network and asset identifiers.
- Dynamic payTo routing so pricing and payouts can vary per request, marketplace, or tenant.
- Extension-first spec design that lets teams add features without changing the core protocol.
- Wallet-based access foundations that enable reusable sessions instead of paying for every call.
- Automatic discovery so facilitators can crawl and keep API metadata current.
- Multi-facilitator support and plugin-driven SDKs that avoid internal edits.
Why it matters
V2 makes x402 viable for higher frequency workloads where round trips and onchain steps are too costly. It also opens the door to subscription-style access, multi-step flows, and richer payment routing, without changing API surfaces.
The launch keeps backward compatibility with V1 while making the standard easier to extend across new networks, transports, and payment models.