Servidor MCP alojado y pagos x402

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Introduction

Accountless website, company and technology intelligence paid with USDC on Base. No BuiltWith account or API key is required.

This is the x402 payment service. The separate Agent Stripe Credit Top-Up API charges an existing account's saved card and is not x402.
Choose an x402 access mode
Use caseFlowCredentialDiscovery
One lookupPay each /agent/* HTTP requestx402 payment proof/openapi.json
Repeated MCP lookupsBuy reusable lookup units once, then spend them with x402-* toolscreditKey/.well-known/x402
HTTP pay-per-call flow
  1. Send the intended request to the narrowest operation under /agent/*.
  2. Read the x402 v2 requirements from the HTTP 402 PAYMENT-REQUIRED header.
  3. Sign the Base USDC payment.
  4. Retry the identical request with the proof in PAYMENT-SIGNATURE.
  5. Read the BuiltWith result and settlement proof in PAYMENT-RESPONSE.

Every /agent/* lookup currently costs $0.0495 USDC. Validation and upstream failures are not settled. GET /agent/domain accepts query parameters; the other operations accept JSON request bodies.

GET https://api.builtwith.com/agent/domain?domain=example.com&liveOnly=true
HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: <base64 x402 v2 requirements>
GET https://api.builtwith.com/agent/domain?domain=example.com&liveOnly=true
PAYMENT-SIGNATURE: <base64 signed x402 v2 payload>
MCP prepaid lookup-unit flow

Connect an MCP client to https://api.builtwith.com/mcp. Standard tools accept a BuiltWith API key in Authorization: Bearer YOUR_BUILTWITH_API_KEY. Alternatively, connect without an account or API key and purchase non-expiring x402 lookup units with USDC on Base.

Call the free x402-pricing tool with an optional credit quantity to get a batch quote. Then call x402-credit-purchase with at least 2,000 credits and the payer wallet, sign the returned x402 v2 payment requirement, and retry with the payment payload in MCP request metadata at _meta["x402/payment"]. Store the returned secret creditKey and supply it to subsequent x402-* lookup tools. Provide an existing key when purchasing another batch to top it up.

Later lookups deduct stored units and do not make another blockchain payment. x402-credit-balance checks the key's remaining units without consuming one. Failed BuiltWith API calls release their credit reservation. List and committed Ask access use separately purchased 30-day passes tied to the payer wallet and returned passToken.

Store a newly returned creditKey securely. Its plaintext value is shown only when the key is created.

Authoritative configuration
  • Protocol: x402 v2
  • Network: Base mainnet (eip155:8453)
  • Asset: USDC, 6 decimals, contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
  • Live facilitator, receiving wallet, prices and inventory: https://api.builtwith.com/.well-known/x402

Clients must read the live descriptor and payment challenge instead of hard-coding the facilitator, wallet, network, asset or price.

Machine references: x402 OpenAPI · x402 descriptor · LLM guide · complete MCP tool list.