payapi-mcp

MCP server for PayAPI Market UK data APIs callable by AI agents via x402 micropayments on Base.

Pay-per-call UK property data with no API keys, no signup, no monthly bills. Install once, ask Claude, and the agent pays USDC per call automatically.

Quick start

Install:

npm install -g payapi-mcp

Add to your Claude Desktop config at ~/Library/Application Support/Claude/claude_desktop_config.json :

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

Restart Claude Desktop, then ask:

Is 12 Acomb Road, York a licensed HMO?

Claude will call uk_hmo_check, pay $0.020 USDC via x402 on Base mainnet, and give you the answer.

Available tools (v0.2)

HMO Licensing — hmo.payapi.market

• uk_hmo_check $0.020/call — Check whether a UK property is a licensed House in Multiple Occupation. Input: postcode + house number/name.
• uk_hmo_by_postcode $0.030/call — List all licensed HMOs in a postcode area. Useful for portfolio analysis and neighbourhood due diligence.
• uk_hmo_licence_details $0.040/call — Full licence record by licence number and council slug. Returns licensee, conditions, occupancy limits, and expiry.

Property Tax — property.payapi.market

• uk_property_stamp_duty $0.001/call — UK Stamp Duty Land Tax calculator with first-time buyer relief and surcharge logic. Returns total tax, effective rate, and band-by-band breakdown.

Example prompts

Is 12 Archers Road, Eastleigh a licensed HMO?

List all licensed HMOs in postcode SE12 9JQ.

Give me the full licence record for LN/202402681 in Lewisham.

What is the stamp duty on a £475,000 property as a first-time buyer?

How it works

PayAPI Market exposes UK data APIs as x402-enabled HTTP endpoints. Each call returns a 402 Payment Required challenge. Your AI agent pays a tiny USDC micropayment on Base mainnet, then receives the data.

Wallet

The package ships with a small free trial pool. When that runs out, set PAYAPI_PRIVATE_KEY to your own Base wallet:

{
  "mcpServers": {
    "payapi-mcp": {
      "command": "npx",
      "args": ["payapi-mcp"],
      "env": {
        "PAYAPI_PRIVATE_KEY": "0xYOUR_PRIVATE_KEY"
      }
    }
  }
}

Network

• USDC on Base mainnet (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913)
• Settlement via Coinbase Developer Platform x402 facilitator
• Indexed on Coinbase Agentic.Market

HMO data coverage

The HMO register covers councils across England and Wales. Coverage grows weekly as new council registers are scraped and indexed.

Links

• Web: https://payapi.market
• HMO API: https://hmo.payapi.market
• Twitter: https://twitter.com/ParkerChet
• x402 protocol: https://x402.org

Licence

MIT