CoinMarketCap Crypto Data

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "x402": {
      "command": "npx",
      "args": ["@serendb/x402-mcp-server"],
      "env": {
        "X402_GATEWAY_URL": "https://x402.serendb.com",
        "WALLET_PRIVATE_KEY": "0x...",
        "BASE_RPC_URL": "https://mainnet.base.org",
        "SERENDB_CONNECTION_STRING": "postgresql://..."
      }
    }
  }
}

Replace 0x... with your wallet private key and postgresql://... with your SerenDB connection string.

claude mcp add x402 \
  -e X402_GATEWAY_URL=https://x402.serendb.com \
  -e WALLET_PRIVATE_KEY=0x... \
  -e BASE_RPC_URL=https://mainnet.base.org \
  -e "SERENDB_CONNECTION_STRING=postgresql://..." \
  -- npx -y @serendb/x402-mcp-server

claude mcp add x402 `
  -e X402_GATEWAY_URL=https://x402.serendb.com `
  -e WALLET_PRIVATE_KEY=0x... `
  -e BASE_RPC_URL=https://mainnet.base.org `
  -e "SERENDB_CONNECTION_STRING=postgresql://..." `
  '--' npx -y @serendb/x402-mcp-server

Replace 0x... with your wallet private key and postgresql://... with your SerenDB connection string.

gemini mcp add x402 \
  -e X402_GATEWAY_URL=https://x402.serendb.com \
  -e WALLET_PRIVATE_KEY=0x... \
  -e BASE_RPC_URL=https://mainnet.base.org \
  -e "SERENDB_CONNECTION_STRING=postgresql://..." \
  -- npx -y @serendb/x402-mcp-server

Replace 0x... with your wallet private key and postgresql://... with your SerenDB connection string.

codex mcp add x402 \
  --env X402_GATEWAY_URL=https://x402.serendb.com \
  --env WALLET_PRIVATE_KEY=0x... \
  --env BASE_RPC_URL=https://mainnet.base.org \
  --env "SERENDB_CONNECTION_STRING=postgresql://..." \
  -- npx -y @serendb/x402-mcp-server

First, install globally to avoid timeout issues:

npm install -g @serendb/x402-mcp-server

Then add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "x402": {
      "command": "x402-mcp-server",
      "args": [],
      "env": {
        "X402_GATEWAY_URL": "https://x402.serendb.com",
        "WALLET_PRIVATE_KEY": "0x...",
        "BASE_RPC_URL": "https://mainnet.base.org",
        "SERENDB_CONNECTION_STRING": "postgresql://..."
      }
    }
  }
}

1. Send your query request to the gateway
2. Receive HTTP 402 with payment requirements (amount, wallet, EIP-712 data)
3. Sign the payment authorization with your wallet
4. Retry request with X-PAYMENT header containing the signature
5. Receive your data - payment settles automatically via USDC on Base

curl -X POST https://x402.serendb.com/api/proxy \
  -H "Content-Type: application/json" \
  -d '{
    "publisherId": "46116003-cdb8-414d-bdca-c80ec7ff95b5",
    "agentWallet": "0xYourWalletAddress",
    "request": {
      "method": "GET",
      "path": "/endpoint"
    }
  }'

This returns 402 Payment Required with the payment details you need to sign.

After signing the EIP-712 authorization, add the base64-encoded signature:

curl -X POST https://x402.serendb.com/api/proxy \
  -H "Content-Type: application/json" \
  -H "X-PAYMENT: <base64-encoded-signature>" \
  -d '{ ... }'