@x402-api/mcp-server

MCP server that gives Claude, ChatGPT, and any MCP-compatible AI agent access to pay-per-call crypto/DeFi data via the x402 protocol.

8 tools. No API keys. AI agents pay USDC micropayments on Base, per request.

Find this service: Official MCP Registry · Glama · Agent discovery manifest · OpenAPI.

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Tools

| Tool | API Endpoint | Cost | Description | |------|-------------|------|-------------| | get_crypto_prices | GET /api/price-feed | 0.001 USDC | BTC/ETH/SOL + top 24h movers | | get_gas_prices | GET /api/gas-tracker | 0.001 USDC | Multi-chain gas (ETH, Base, Polygon, Arbitrum) | | get_dex_quotes | GET /api/dex-quotes | 0.002 USDC | One ParaSwap aggregate route | | scan_token | GET /api/token-scanner | 0.003 USDC | GoPlus security flags and heuristic | | track_whales | GET /api/whale-tracker | 0.005 USDC | Top-holder sample and supply share | | scan_yields | GET /api/yield-scanner | 0.005 USDC | DefiLlama pool APYs and TVL | | get_funding_rates | GET /api/funding-rates | 0.008 USDC | Hyperliquid and dYdX hourly rates | | profile_wallet | GET /api/wallet-profiler | 0.008 USDC | Observed Blockscout balances; partial coverage |

Quick Start

Option A: Inspect mode (no payment needed)

Just run it — any 402 responses will return human-readable payment instructions:

npx @x402-api/mcp-server

Claude will tell you what's needed when a tool requires payment.

Option B: Auto-pay mode (fully autonomous)

Install optional payment deps and set your wallet key:

npm install -g @x402-api/mcp-server
npm install -g viem
export X402_WALLET_PRIVATE_KEY=0x<your_private_key>
x402-api-mcp

The MCP server signs Base USDC EIP-3009 authorizations only when the API advertises that settlement mode. The default payment cap is 0.01 USDC per call. Fund the wallet with USDC on Base; the API operator sponsors gas in direct settlement mode.

Claude Desktop Integration

Add to your claude_desktop_config.json:

Without auto-pay (inspect mode)

{
  "mcpServers": {
    "x402-api": {
      "command": "npx",
      "args": ["@x402-api/mcp-server"]
    }
  }
}

With auto-pay

{
  "mcpServers": {
    "x402-api": {
      "command": "npx",
      "args": ["@x402-api/mcp-server"],
      "env": {
        "X402_WALLET_PRIVATE_KEY": "0x<your_private_key>"
      }
    }
  }
}

Config file location:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Environment Variables

| Variable | Required | Description | |----------|----------|-------------| | X402_WALLET_PRIVATE_KEY | Optional | Base wallet private key for EIP-3009 automatic payment. Requires viem. | | X402_MAX_PER_CALL_USDC | Optional | Per-call cap, default 0.01 USDC. | | X402_API_BASE_URL | Optional | Override API URL (default: https://x402-api.fly.dev) |

How x402 Payments Work

This API uses the x402 protocol — HTTP 402 Payment Required:

1. Agent calls tool → MCP server makes API request
2. Server returns 402 with payment details (amount, USDC address, Base network)
3. Auto-pay mode: this client signs an EIP-3009 authorization and retries; the API settles it on Base
4. Inspect mode: MCP returns 402 details without signing or paying

Payment details:

• Token: USDC on Base mainnet
• Address: 0x60264c480b67adb557efEd22Cf0e7ceA792DefB7
• Chain: Base (chain ID 8453)
• Amount: 0.001–0.008 USDC per call (< 1 cent USD)

Tool Reference

get_crypto_prices

No parameters. Returns current prices for BTC, ETH, SOL + top 24h movers.

Cost: 0.001 USDC

get_gas_prices

No parameters. Returns gas prices for Ethereum, Base, Polygon, Arbitrum — slow/standard/fast tiers.

Cost: 0.001 USDC

get_dex_quotes

Get one ParaSwap aggregate route. No independent comparison between DEX venues.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | from | string | ✅ | Input token (e.g. "ETH", "0x...") | | to | string | ✅ | Output token (e.g. "USDC") | | amount | string | ✅ | Amount to swap (e.g. "1.5") |

Cost: 0.002 USDC

scan_token

Token security scan — detects rug-pull flags, honeypot patterns, mint authority, etc.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | token | string | ✅ | Contract address or symbol (e.g. "PEPE") |

Cost: 0.003 USDC

track_whales

Top-holder sample from GoPlus. Gini and recent transfer history unavailable.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | token | string | ✅ | Contract address or symbol |

Cost: 0.005 USDC

scan_yields

Top DeFi yield opportunities across Aave, Compound, Morpho, Lido, Pendle, etc.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | chain | string | ❌ | Filter by chain: "ethereum", "base", "arbitrum", "polygon" | | min_tvl | number | ❌ | Minimum TVL in USD (e.g. 1000000) |

Cost: 0.005 USDC

get_funding_rates

Hourly perpetual funding from Hyperliquid and dYdX v4. Spreads are indicative.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | asset | string | ❌ | Asset symbol (e.g. "BTC", "ETH"). All assets if omitted. |

Cost: 0.008 USDC

profile_wallet

Observed priced wallet balances and available transaction counts. DeFi positions, PnL and risk score unavailable.

| Parameter | Type | Required | Description | |-----------|------|----------|-------------| | address | string | ✅ | Ethereum/Base wallet address (0x...) |

Cost: 0.008 USDC

Development

git clone https://github.com/fernsugi/x402-api-mcp-server
cd x402-api-mcp-server

npm install
npm run build
npm start

To test without a payment wallet, simply run and see the 402 responses:

node dist/index.js

Links

• x402 API Landing Page
• x402 Protocol
• Base Chain
• ERC-8004 Agent Identity
• Agent #18763 on BaseScan

License

MIT

Three runnable workflows

| Workflow | Tools | Total USDC | |---|---|---:| | Token check | scan_token + track_whales | 0.008 | | ETH funding | get_funding_rates | 0.008 | | Swap quote + gas | get_dex_quotes + get_gas_prices | 0.003 |

Runnable Node examples start in inspect mode. Each demo has inputs, recorded provider output, coverage limits, a spending cap, and an agent prompt.

Optional X402_REFERRAL_SOURCE labels requests for first-party aggregate attribution (default mcp). It is a hint, not verified caller identity. The API journals no raw payer wallets, IP addresses, or signatures. X402_EXPECTED_PAY_TO pins the payment recipient to the official wallet by default. Tools advertise that auto-pay can spend money and repeated calls can incur another charge.

Cursor / other local MCP clients

Use the same mcpServers configuration shown above. For Cursor, put it in .cursor/mcp.json in your project. Inspect mode needs no wallet. Set X402_MAX_PER_CALL_USDC before enabling auto-pay; repeated calls spend again. Keep wallet credentials in local environment settings, outside Git.