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x402-go Overview

x402-go is a Go implementation of the x402 protocol, enabling verifiable on-chain payments. The project provides comprehensive tools for payment verification and settlement across blockchain networks.

What is x402?​

The x402 protocol (as defined by Coinbase) facilitates cryptographically verifiable payment transactions. It enables services to require and validate payments before granting resource access, creating a trustless payment verification system.

Components​

Facilitator Service​

The backend payment processor providing three main endpoints:

  • GET /supported - Lists available payment scheme-network combinations
  • POST /verify - Validates payment payloads
  • POST /settle - Finalizes payments on blockchain

Facilitator Client​

A library for interacting with x402 facilitator services:

  • Query supported payment schemes and networks
  • Verify payment authenticity and validity
  • Settle payments and obtain transaction confirmations

Middleware​

Gin-based middleware for protecting HTTP APIs with payment requirements:

  • Define default payment requirements per route
  • Automatically validate incoming x402 payment headers
  • Enforce selective protection on specified paths

Resource Client​

Consumer-facing library enabling explicit payment flow management:

  • Detect payment requirements
  • User-driven decision-making on payment acceptance
  • Automated payment transmission with settlement confirmation

Use Cases​

  • API Monetization - Require payment for API access without traditional subscription models
  • Pay-per-Use Services - Charge users per request or resource access
  • Content Gating - Require payment before serving premium content
  • Microservices - Enable payment requirements between services

Source Code​

View the source code and contribute on GitHub: vorpalengineering/x402-go