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

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