GPT-5.5 x402 API Gateway

Fetch a public x402/API service, audit machine-readable discovery, compare directory visibility, inspect live pricing signals, and return ranking gaps plus concrete listing SEO fixes for x402 marketplaces. This deterministic endpoint does not call an upstream model. GET variant for agents, crawlers, and wallets that prefer query parameters over a JSON body. Pay up to $0.008 per request with x402 USDC on Base.

Call it in 30 seconds

// npm i x402-fetch viem
import { wrapFetchWithPayment } from "x402-fetch";
import { createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { base } from "viem/chains";

const account = privateKeyToAccount(process.env.PRIVATE_KEY); // funds USDC on Base
const wallet = createWalletClient({ account, chain: base, transport: http() });
const fetchWithPay = wrapFetchWithPayment(fetch, wallet);

// Pays the $0.008 USDC automatically on the 402, then returns the real response:
const res = await fetchWithPay("https://gpt55.558686.xyz/v1/tools/x402-listing-seo-audit", { method: "GET" });
console.log(await res.json());

# pip install x402 eth-account httpx
import os, asyncio
from eth_account import Account
from x402.clients.httpx import x402HttpxClient

account = Account.from_key(os.environ["PRIVATE_KEY"])  # funds USDC on Base

async def main():
    async with x402HttpxClient(account=account) as client:
        # x402 handles the 402 -> pay ($0.008 USDC) -> retry automatically
        r = await client.get("https://gpt55.558686.xyz/v1/tools/x402-listing-seo-audit")
        print((await r.aread()).decode())

asyncio.run(main())

# 1) An unpaid request returns HTTP 402 with the exact payment terms:
curl -i "https://gpt55.558686.xyz/v1/tools/x402-listing-seo-audit?include_market=True&query=gpt-5.5 x402&url=https://gpt55.558686.xyz"

# 2) Paying + retrying requires an x402 client that can sign the USDC
#    authorization (curl alone cannot). See the JS / Python tabs below.

New to x402? Read the 5-minute quickstart →