APEX IBIS | x402 AI Agent Exchange

Purchase an API request with an x402 client

1. Discover: Use POST and Content-Type: application/json. An unpaid request returns HTTP 402 and PAYMENT-REQUIRED; it does not charge you. GET only shows the endpoint documentation.

curl -i -X POST https://apexibis.com/verify-citation -H "Content-Type: application/json" --data '{"claim":"The United States declared war on Japan on December 8, 1941.","sourceUrl":"https://www.archives.gov/milestone-documents/joint-address-to-congress-declaration-of-war-against-japan"}'

2. Prepare: Install packages locally with npm install @x402/fetch @x402/core @x402/evm viem. Use a dedicated low-balance Base Mainnet wallet containing USDC and some ETH. Keep your private key in a local environment variable, never in a website or message.

3. Pay and retry: Save the code below to buy.mjs; set EVM_PRIVATE_KEY locally; run node buy.mjs. The quote guard accepts only exactly $0.01 USDC on Base and only the configured recipient.

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { ExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const key = process.env.EVM_PRIVATE_KEY;
if (!/^0x[0-9a-fA-F]{64}$/.test(key || "")) throw Error("Missing wallet key");
const client = new x402Client();
client.register("eip155:8453", new ExactEvmScheme(privateKeyToAccount(key)));
client.onBeforePaymentCreation(async ({ selectedRequirements: q }) => {
  const valid = q.network === "eip155:8453" &&
    q.scheme === "exact" && BigInt(q.amount) === 10000n &&
    q.payTo?.toLowerCase() === "0xfbc4f75278c9f3c901efada9feb3de76089fcb99" &&
    q.asset?.toLowerCase() === "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913";
  return valid ? undefined : { abort: true, reason: "Unexpected payment terms" };
});
const paidFetch = wrapFetchWithPayment(fetch, client);
const response = await paidFetch("https://apexibis.com/verify-citation", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    claim: "The United States declared war on Japan on December 8, 1941.",
    sourceUrl: "https://www.archives.gov/milestone-documents/joint-address-to-congress-declaration-of-war-against-japan"
  })
});
if (!response.ok) throw Error("Request failed: HTTP " + response.status);
console.log(await response.json());

For other endpoints, inspect the service's actual x402 quote and enforce its price before paying. A 415 response means the client sent the wrong Content-Type; fix the JSON request before attempting payment.