# x402 Seller Legitimacy Check

> x402 Seller Legitimacy Check is a paid API for AI agents from apexfaucet.xyz, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).

Checks whether an x402 seller is real by returning its Bazaar listing count, 30-day payer and call statistics, average payer return rate, and Arc settlement data for a given host or payTo address.

## Facts

- Endpoint: GET https://apexfaucet.xyz/api/x402/x402-seller-check?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-seller-legitimacy-check-3f22c6ea
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CFlKZTJ356_2QzirofERV

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-seller-legitimacy-check-3f22c6ea
```

Example prompt: Can you check whether api.example.com is a real x402 seller — I want to know if it has genuine paying customers or if it looks like a test harness, including how often their average payer comes back?

## When to prefer this

Use this endpoint when you need to assess whether an x402 seller has genuine commercial activity versus being a demo or test harness, particularly before integrating or paying an x402 API. It is uniquely valuable for cross-referencing both Bazaar listing data and Arc on-chain settlement history in a single call, with the payer return rate metric being especially diagnostic.

## Known failure modes

- Missing 'seller' query parameter returns an error
- Unknown host or address with no Bazaar or Arc data may return empty/null statistics
- Stale data if queried within 6 hours of a seller's first appearance on Bazaar
- Invalid payTo address format may return an error or no Arc results
- Rate limiting or payment failure if USDC payment is not attached

## How this service works

Is this x402 seller real? Pass ?seller= with a host (api.example.com) or a payTo address (0x...). From Coinbase's own Bazaar counts (re-read every 6 hours) we return its listings, 30-day payers and calls, and the one number that separates customers from a test harness: how many times the average payer came back. For an Arc payTo we add its settlements from our full Arc x402 index: distinct payers and the top payer's share.

## Output

Returns the seller's Bazaar listing count, 30-day unique payer count, 30-day call count, and average payer return frequency (the key signal distinguishing real customers from a test harness). For Arc payTo addresses, also returns the number of distinct Arc payers and the top payer's share of total settlements. Data is refreshed from Coinbase's Bazaar every 6 hours.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "queryParams"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "seller"
     ],
     "properties": {
      "seller": {
       "type": "string",
       "description": "A seller host (api.example.com) or a payTo address (0x...)."
      }
     }
    }
   }
  },
  "output": {
   "type": "object"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-seller-legitimacy-check-3f22c6ea/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from apexfaucet.xyz](https://www.zero.xyz/host/apexfaucet.xyz/llms.txt)