x402-fetch-mcp

MCP (Model Context Protocol) server that enables AI agents to automatically pay for and access paywalled content using the x402 payment protocol.

What is x402?

x402 is a payment protocol that uses HTTP status code 402 (Payment Required) to enable micropayments for web content. When an AI agent encounters a 402 response, this MCP server automatically handles the payment using USDC on Base network.

Features

• Automatic Payments: Seamlessly handles 402 Payment Required responses
• Secure Key Storage: Private keys stored in ~/.x402/config.json (not environment variables)
• Base Network Support: Works with Base Sepolia (testnet) and Base (mainnet)
• Claude Code Integration: Works directly with Claude Code via MCP

Quick Start

1. Install and Setup

# Run the setup wizard
npx x402-fetch-mcp setup

You'll be prompted for:

• Private Key: Your wallet's private key (0x... format)
• Network: baseSepolia (testnet) or base (mainnet)

2. Add to Claude Code

claude mcp add x402 -- npx x402-fetch-mcp

3. Verify Installation

claude mcp list
# Should show: x402 - ✓ Connected

Usage

Once installed, Claude Code can automatically access paywalled content:

User: Fetch the content from https://learn402.xyz/demo/protected-content

Claude: I'll use the x402_fetch tool to access this paywalled content...
[Automatically pays $0.01 USDC and retrieves content]

Available Tools

x402_fetch

Fetches content from a URL with automatic x402 payment support.

Parameters:

• url (required): The URL to fetch
• method (optional): HTTP method (GET, POST, etc.)
• headers (optional): Additional headers
• body (optional): Request body for POST/PUT

x402_wallet_info

Returns information about the configured wallet.

Configuration

Config file location: ~/.x402/config.json

{
  "privateKey": "0x...",
  "network": "baseSepolia"
}

Check Configuration

npx x402-fetch-mcp-setup info

Update Configuration

npx x402-fetch-mcp setup
# Choose 'y' to overwrite existing config

Security

• Private keys are stored in ~/.x402/config.json with 600 permissions
• Keys are NOT stored in environment variables (prevents exposure via env command)
• Never share your config file or commit it to version control

Network Support

Network	Chain ID	USDC Contract
Base Sepolia	84532	0x036CbD53842c5426634e7929541eC2318f3dCF7e
Base	8453	0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Getting Test USDC

For Base Sepolia testnet:

1. Get testnet ETH from Base Sepolia Faucet
2. Get test USDC from Circle Faucet

Demo

Try the x402 payment flow at learn402.xyz

License

MIT