SELF-SERVICE INTEGRATION

Your first paid call.

Choose an endpoint, send JSON, approve its exact x402 quote, and save the result and settlement receipt. The service needs no account, deposit, or API key.

Use the client helper

The client helper checks the Base network, native USDC asset, recipient, exact price, and resource URL before your signer authorizes payment. Use a caller-controlled wallet funded with USDC on Base. Keys stay in your application or wallet.

npm install @x402/core@2.23.0 @x402/evm@2.23.0 viem

// Download and inspect /client.mjs, then keep it in your project.
import { createGuardClient } from './client.mjs';
// signer is your existing caller-controlled EVM wallet signer.
const guard = createGuardClient(signer);
const { report, receipt } = await guard.call('/api/domain-audit', {
  domain: 'example.com'
});
console.log(report.findings, receipt.transaction);

The signer must provide an EVM address and signTypedData, as expected by the x402 EVM SDK. A Coinbase exchange account alone is not an agent signer. Existing wallet and agent SDKs can supply the signer.

Probe without paying

curl -i https://x402.momentbolt.com/api/domain-audit \
  -H 'Content-Type: application/json' \
  -d '{"domain":"example.com"}'

Expect HTTP 402 and a PAYMENT-REQUIRED header containing base64-encoded JSON. This probe cannot charge your wallet. Decode and inspect it before using a payment client.

Check the receipt

A successful paid call returns HTTP 200, the purchased JSON, and PAYMENT-RESPONSE. Decode the receipt and retain its transaction hash. Verify the transaction transferred the exact native USDC amount to the advertised recipient on Base.

Errors and retries

For agents

Use the OpenAPI contract, agent skill, or MCP discovery guide. Ordinary LLM chat cannot pay automatically without a wallet-capable client.

Support

Email admin@momentbolt.com with the request ID and public transaction hash. Never send seed phrases, private keys, or payment signatures.