GoldBean MCP Server

🫘 GoldBean - x402 Micropaid API Marketplace

Pay per request with USDC on Base. No signup, no API key, no monthly subscription. Every call costs $0.02 USDC via the x402 protocol.

GoldBean is live: http://104.225.233.23:9879

Quick Start

1. Prerequisites

• USDC on Base (eip155:84532 testnet or eip155:8453 mainnet)
• A wallet that can sign x402 payments (AgentCash, CDP Wallet, or any EVM wallet)

2. Try a Free Endpoint

curl http://104.225.233.23:9879/health
# {"status":"ok","service":"GoldBean","timestamp":"2026-05-15T12:00:00.000Z"}

curl http://104.225.233.23:9879/eth-price
# {"usd":"2255.93","change24h":"+0.31%","timestamp":"2026-05-15T12:00:00.000Z"}

3. Call a Paid Endpoint

curl http://104.225.233.23:9879/paid/btc-price
# HTTP 402 Payment Required
# x402-challenge: {...}

To pay the 402 and get data, you need an x402-capable client:

Using AgentCash:

npx agentcash@latest fetch http://104.225.233.23:9879/paid/btc-price

Using x402-proxy (CLI tool):

npx x402-proxy http://104.225.233.23:9879/paid/btc-price

Using curl with manual payment (advanced):

# Step 1: Request triggers 402
curl -s -D - http://104.225.233.23:9879/paid/btc-price

# Step 2: Parse x402-challenge header, sign with your wallet
# Step 3: Retry with x402-payment header
curl -H "x402-payment: <signed-payment>" http://104.225.233.23:9879/paid/btc-price

4. MCP Integration

Add to Claude Desktop / Cursor / Cline mcpServers config:

{
  "mcpServers": {
    "goldbean": {
      "url": "http://104.225.233.23:9879/mcp"
    }
  }
}

Available Endpoints

Free (no payment needed)

Paid ($0.02 USDC per call)

How x402 Payment Works

Client                          GoldBean Server
  │                                   │
  ├─ GET /paid/btc-price ─────────────┤
  │◄─ 402 Payment Required ───────────┤
  │   x402-challenge: {...}           │
  │                                   │
  ├─ Sign challenge with wallet ──────┤
  │   (off-chain, no gas fee)         │
  │                                   │
  ├─ GET /paid/btc-price ─────────────┤
  │   x402-payment: <signed>          │
  │◄─ 200 OK ─────────────────────────┤
  │   {"usd":"68000.00",...}          │
  │                                   │

The facilitator (x402.org) handles settlement. Your wallet sends USDC only when challenge is accepted. No recurring charges.

Data Sources

• CoinGecko API — Real-time cryptocurrency prices
• Etherscan API — Gas price oracle
• Alternative.me — Fear & Greed Index

Seller Info

• Seller wallet: 0xB5f5CBe48E0595C044Bc626f278F757463eAc2Ce (Base)
• Network: eip155:84532 (Base Sepolia testnet) → migrating to eip155:8453 (Base mainnet)
• Facilitator: https://x402.org/facilitator
• Price: $0.02 USDC per paid call

Architecture

┌─────────────┐     x402 protocol      ┌──────────────┐
│   Client    │ ◄─────────────────────► │   VPS (USCA) │
│ (curl/Agent)│     HTTP + 402 flow     │  GoldBean 🫘 │
└─────────────┘                         │  :9879       │
       │                                └──────┬───────┘
       │         ┌──────────────┐              │
       └────────►│    Email     │◄─────────────┘
                 │  (Gmail)     │  Monitor alerts
                 │   Monitor    │
                 └──────────────┘

Development

# Server
cd /opt/goldbean
npm install express axios @x402/express @x402/core @x402/evm
node server.js

# Monitor
python3 /opt/goldbean/chain_monitor.py

Ecosystem

• x402 Foundation
• Awesome x402
• x402 TypeScript SDK

Built on Bandwagon VPS (USCA-2). Part of the x402 ecosystem.