x402 Stellar MCP Server

Local MCP server (stdio) that can call x402-protected HTTP resources and automatically pay in Stellar USDC.

Features

• Payment flow (stellar:testnet or stellar:pubnet)
• Default testnet configuration
• Mainnet-ready via env switch
• Optional OpenZeppelin facilitator auth via env
• No resource whitelist: URL is provided at tool call time

Tools Exposed

• x402_wallet_info: shows active wallet address/network/config
• x402_facilitator_supported: checks configured facilitator /supported endpoint
• fetch_paid_resource: generic paid fetch (url, method, optional body/headers)

Prerequisites

• Node.js 20+
• A Stellar wallet funded with testnet XLM + testnet USDC
• x402 resource server running (your app/index.js demo)
• x402 facilitator running on http://localhost:4022

Setup

npm install
cp .env.example .env

Testnet

For testnet you'll need to run a facilitator locally on port 4022. I'd recommend using the one included in the coinbase x402 repo: https://github.com/coinbase/x402/tree/main/examples/typescript/facilitator/advanced

Update .env with your wallet key:

STELLAR_SECRET_KEY=S...
STELLAR_NETWORK=stellar:testnet

Pubnet

For mainnet you'll just need an OpenZeppelin API Key for the relayer. You can get one here (Thank you for making this easy): https://channels.openzeppelin.com/gen

STELLAR_NETWORK=stellar:pubnet
STELLAR_RPC_URL=https://rpc.lightsail.network/
X402_FACILITATOR_URL=https://channels.openzeppelin.com/x402
X402_FACILITATOR_API_KEY=<your-openzeppelin-api-key>

X402_FACILITATOR_API_KEY is optional in general, but required for OpenZeppelin channels. When set, fetch_paid_resource auto-adds Authorization: Bearer <key> for requests under X402_FACILITATOR_URL (unless you provide Authorization explicitly).

Run

npm run dev

The MCP server runs over stdio for Claude/Codex integrations.

Add To Claude / Codex

Use an MCP entry like (don't forget to change the path/):

Codex

codex mcp add x402-stellar -- npm --silent --prefix /absolute/path/to/x402-mcp-stellar run dev

Claude Code

claude mcp add x402-stellar -- npm --silent --prefix /absolute/path/to/x402-mcp-stellar run dev

Claude Desktop (untested)

{
  "mcpServers": {
    "x402-stellar": {
      "command": "npm",
      "args": ["--silent", "--prefix", "/absolute/path/to/x402-mcp-stellar", "run", "dev"]
    }
  }
}

This server loads .env from the project directory (/absolute/path/to/x402-mcp-stellar/.env).

Claude Usage

After loading the MCP server, you can ask:

Can you fetch the resource at http://localhost:3000/my-service, use the x402-stellar MCP server to pay for it, and print the response?

The tool call will pass that full URL at runtime; no URL allowlist or hardcoded endpoint is required in this MCP server.

Notes

• @x402/stellar is not currently published on npm, so this repo vendors the Stellar mechanism under src/stellar.
• Default testnet Soroban RPC is used automatically.
• Mainnet requires STELLAR_RPC_URL.

License

MIT