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x402 Protocol Overview ​

Coinbase x402 is the open payment layer for Web3. It extends the HTTP 402 Payment Required status so any API, website, or agent can exchange value instantly without accounts, emails, or multi-step onboarding. Builders use x402 to ship paid experiences that feel as fast as streaming data.

Why a Payment Layer for the Web ​

  • Traditional payment stacks add delays, compliance overhead, and settlement risk that break real-time experiences.
  • Information now moves at the speed of packets; value should do the same so creators, APIs, and agents can unlock new business models.
  • HTTP already defines 402 Payment Required. x402 operationalizes it with programmable flows that work across browsers, SDKs, and autonomous systems.

Core Capabilities ​

  • One Protocol. Infinite Economies. Meter content, APIs, tasks, and community access through a single programmable primitive.
  • Instant Settlement. Every interaction resolves on-chain in seconds, enabling trustless micropayments across borders.
  • Accountless Access. Consumers pay from self-custodial wallets or embedded agents; no passwords or email capture required.
  • Composable APIs. REST and webhook surfaces let developers bolt x402 onto existing services or agentic workflows with minimal code.
  • Policy Control. Dynamic pricing, rate limits, and credit allowances give operators fine-grained control over value exchange.

Typical Payment Flow ​

  1. A client requests a resource that is protected by an x402 paywall.
  2. The server responds with 402 Payment Required, including payment terms and a Coinbase x402 invoice link.
  3. The client signs and broadcasts the payment using the preferred wallet or agent runtime.
  4. x402 confirms settlement and notifies the origin via webhook so the resource can be delivered instantly.

Builder Integrations ​

  • Web Content. Gate premium articles, video streams, or research downloads with per-request pricing.
  • API Providers. Expose endpoints for data, AI inference, or SaaS features with pay-per-call billing.
  • Tasks Marketplace. Match human contributors and AI agents, settling per task or deliverable without escrow delays.
  • Community Gating. Introduce fee-based access to forums or live events to reduce spam and reward contribution.

Next Steps ​