Microtap MCP

microtap-mcp

An MCP server for MicroTap — 20 pay-per-call APIs (Polymarket & Kalshi prediction markets, cross-platform prediction-market divergence, DeFi/crypto data, multi-chain on-chain reads, live weather, real-time web search) paid for automatically in USDC via the x402 protocol. No signup, no API key, no dashboard — install it, fund a small local wallet, and your AI assistant can start calling paid endpoints on its own.

Quick start

Add it to your MCP client's config. On first run it auto-generates a local EVM wallet — you don't need to create one yourself.

Claude Desktop / Claude Code

{
  "mcpServers": {
    "microtap": {
      "command": "npx",
      "args": ["-y", "microtap-mcp"]
    }
  }
}

Cursor / Windsurf

Same config shape — add the block above under whichever mcpServers config file your client uses.

After adding it, restart your client, then look at the server's startup log (in Claude Desktop: Settings → Developer → microtap → logs) for a line like:

[microtap-mcp] wallet address: 0xabc123...
[microtap-mcp] fund this address with a small amount of USDC on Base mainnet to pay for calls

Send a few dollars of USDC on Base mainnet to that address — at $0.01 per call for most tools (up to $0.05), $5 covers a few hundred calls. Your assistant can now use any of the 20 tools below; each one pays for itself automatically.

What it does

Every tool call:

1. Calls the matching route on x402tap.com.
2. If the server responds 402 Payment Required (it always does, the first time), signs a USDC payment for the exact amount requested using the wallet's private key — entirely locally, nothing is sent anywhere except the signed payment itself.
3. Retries the request with the payment attached and returns the real response.

The private key never leaves your machine. It isn't sent to MicroTap, an LLM provider, or anywhere else — it only signs payment messages locally, the same non-custodial pattern used by other x402 MCP servers in this ecosystem (e.g. BlockRun's).

Tools

Full parameter docs for each route: x402tap.com/openapi.json.

Configuration (all optional)

Set these as environment variables in your MCP client's server config ("env": { ... } alongside "command"/"args") if you need to override a default:

The auto-generated wallet's key is stored at ~/.microtap-mcp/wallet.json (created with 0600 permissions — readable only by your user).

Local development

npm install
npm run build
npm start   # runs the compiled server over stdio

Security notes

• The wallet key is only ever used to sign payment messages locally (EIP-712 exact scheme on Base mainnet) — it's never transmitted anywhere.
• MICROTAP_MCP_MAX_VALUE_USDC (default $0.10) means this server will refuse to auto-approve a payment above that amount for a single call, even if a route's advertised price is ever wrong or unexpectedly high.
• All 20 tools are read-only against MicroTap's API surface — none of them can move funds, sign transactions, or write on-chain state (/api/rpc is restricted server-side to a safelist of read-only JSON-RPC methods).

License

MIT