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Introduction to x402

The x402 payment protocol enables instant, onchain payments as part of standard web requests. Built around the HTTP 402 “Payment Required” status code, x402 eliminates the need for redirects, checkout flows, or user accounts, making it ideal for AI agents, autonomous applications, and machine-to-machine transactions. The protocol is blockchain-agnostic, requires no fees, and provides instant settlement while maintaining security through open standards.

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How x402 Works

The x402 protocol follows a simple request-response pattern:
  1. Request: Client makes an HTTP request to an API
  2. 402 Response: Server responds with payment instructions
  3. Payment: Client signs payment and resends request with X-Payment header
  4. Verification: Server or facilitator verifies the payment
  5. Settlement: Payment is submitted to blockchain
  6. Delivery: Server delivers the requested resource

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Buyers and Sellers

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For Buyers

  • No accounts required: Pay without creating accounts or providing personal information
  • Instant payments: Seamless payment experience within HTTP requests
  • Multiple wallet options: Use embedded wallets, external wallets, or server wallets
  • Programmatic: Perfect for AI agents and automated applications

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For Sellers

  • Simple integration: Add payment requirements with minimal code changes
  • Usage-based pricing: Charge per request, per API call, or per resource
  • No payment processing: Facilitators handle blockchain complexity
  • Flexible monetization: Enable micropayments and pay-per-use models

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Dynamic’s Role

Dynamic’s wallet infrastructure handles the payment signing layer, while x402 provides the payment protocol. This combination offers:
  • Seamless UX: Embedded wallets sign payments automatically
  • Multi-wallet support: Works with embedded, external, and server wallets
  • Developer-friendly: Minimal setup using familiar HTTP patterns
  • Scalable: Supports both client-side and server-side payment flows

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Use Cases

x402 with Dynamic enables powerful new monetization models:
  • AI billing: Charge per inference or API call for AI services
  • API monetization: Usage-based pricing instead of subscriptions
  • Autonomous agents: Agents can pay for services automatically
  • Micropayments: Pay-per-article, pay-per-video, or pay-per-data-point
  • Content creators: Instant transactions for premium content

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Facilitators

x402 uses facilitators to handle blockchain complexity. The Coinbase Developer Platform provides:
  • Zero-fee USDC payments on Base
  • Instant settlement with onchain finality
  • Built-in compliance and risk screening
  • Simple integration with minimal setup

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Key Benefits

  • No redirects: Payments happen within HTTP requests
  • No accounts: Users don’t need to create accounts or log in
  • Low fees: Especially for micropayments
  • Instant settlement: Money in your wallet in seconds
  • Universal compatibility: Works with any HTTP client

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Getting Started

Ready to implement x402 payments with Dynamic? Our implementation guide provides detailed code examples and step-by-step instructions for integrating x402 with Dynamic’s wallet infrastructure.
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