# x402 Seller Check

> x402 Seller Check is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.04/call, status unknown (last checked 2026-10-20).

Screens an x402 payment endpoint and/or seller wallet for legitimacy, returning a GO/WARN/STOP signal based on URL validity, price matching, and wallet risk factors like sanctions or throwaway status.

## Facts

- Endpoint: GET https://402.com.tr/api/x402/x402-seller-check?utm_source=zero.xyz
- Price: $0.04/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-seller-check-a1d01f66
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7L_AvqxAggLEnJ-iTdKym

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-check-a1d01f66
```

Example prompt: Before you pay that x402 endpoint at https://api.someservice.com/data, check if the seller wallet 0xAbC123... is legitimate and not sanctioned, and confirm the price actually matches what's advertised — give me a GO, WARN, or STOP.

## When to prefer this

Use this endpoint when an AI agent is about to autonomously pay an x402-gated URL with USDC and needs a pre-flight trust check — especially when the seller is unknown, the payTo address was not previously vetted, or the price advertised seems off. Prefer this over generic wallet checkers because it specifically understands x402 protocol mechanics (price headers, payTo fields, 402 response structure) and combines URL validation with wallet risk signals in a single call.

## Known failure modes

- URL is not reachable or does not return a 402 response — endpoint may report WARN or STOP with connectivity detail
- Wallet address is malformed or not a valid Base address — validation error returned
- Neither url nor payTo provided — missing required input error
- External sanctions or on-chain data temporarily unavailable — may return degraded result or error
- x402 endpoint requires payment itself, creating a bootstrapping check cost of $0.04 USDC per call

## How this service works

x402 proves payment, not trust: an agent handed a URL pays blind, and the payee may be a real service or a burner that takes the USDC and vanishes. Give a url and/or a payTo wallet and get GO/WARN/STOP: is the URL a well-formed 402 resource, does its price match, and is the seller wallet sanctioned, a fresh throwaway, or paying a different address than you expected. Screens the PAYMENT side the protocol drops — not a guarantee the service returns good data.

## Output

Returns a GO, WARN, or STOP decision along with details on: whether the URL is a well-formed x402 resource, whether the price matches expectations, whether the payTo wallet is OFAC-sanctioned, and whether the wallet appears to be a fresh throwaway or unexpectedly different from what the agent anticipated.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "url": {
       "type": "string",
       "description": "x402 endpoint URL"
      },
      "payTo": {
       "type": "string",
       "description": "Seller wallet (optional if url given)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-seller-check-a1d01f66/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402.com.tr](https://www.zero.xyz/host/402.com.tr/llms.txt)