intents

Cross-Store Price Intent

One product query priced across four retail surfaces in a single call: Google Shopping, Amazon, eBay and Walmart.

GET/api/public/v1/cross-store-price

price: $0.020
atomic: 20000
free tier: 3 calls / agent
chain: base mainnet
asset: USDC
scheme: exact

agent brief

Give a product query, get offers from Google Shopping, Amazon, eBay and Walmart.

engine: · results key: results · settlement: USDC / base / exact

use this when you need to

-Best-price selection for a purchasing agent
-Arbitrage scanning
-Retail price-spread analysis

query parameters

name	type	required	description
network	base \| base-sepolia	no · default "base"	Payment network. base-sepolia returns mock data for testing.
q	string	yes	Product query sent to all four retail engines
gl	string	no · default "us"	Country code for results
hl	string	no · default "en"	Interface language code

call it — curl

bash

# Free tier — first 3 calls per agent identity, no payment header
curl "https://marketplaceforaiagents.com/api/public/v1/cross-store-price?q=AI+agents"

# Sandbox — signed testnet USDC, mock response, no real spend
curl "https://marketplaceforaiagents.com/api/public/v1/cross-store-price?q=AI+agents&network=base-sepolia" \
  -H "X-PAYMENT: <base64 signed base-sepolia USDC authorization>"

# Production — signed x402 payment header, real data
curl "https://marketplaceforaiagents.com/api/public/v1/cross-store-price?q=AI+agents" \
  -H "X-PAYMENT: <base64 signed USDC authorization>"

call it — typescript + x402-fetch

typescript

import { wrapFetchWithPayment } from "x402-fetch";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.AGENT_PRIVATE_KEY as `0x${string}`);
const fetchWithPayment = wrapFetchWithPayment(fetch, account);

const res = await fetchWithPayment(
  "https://marketplaceforaiagents.com/api/public/v1/cross-store-price?q=AI+agents"
);
const data = await res.json();
console.log(data.results);

response — 200 ok

application/json

{
  "intent": "cross-store-price",
  "chain": [
    "google-shopping",
    "amazon-search",
    "ebay-search",
    "walmart-search"
  ],
  "steps_run": 4,
  "results": {
    "google-shopping": {
      "note": "Normalized response of /api/public/v1/google-shopping"
    },
    "amazon-search": {
      "note": "Normalized response of /api/public/v1/amazon-search"
    },
    "ebay-search": {
      "note": "Normalized response of /api/public/v1/ebay-search"
    },
    "walmart-search": {
      "note": "Normalized response of /api/public/v1/walmart-search"
    }
  }
}

status codes

200data returned, response includes X-PAYMENT-RESPONSE receipt when paid

400missing or invalid required parameters

402free tier exhausted or invalid X-PAYMENT — body contains accepts[] payment requirements

404unknown endpoint slug

429upstream rate limit — retry with backoff

500upstream or settlement error