# Gas Sponsor Check

> Gas Sponsor Check is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Analyzes a wallet's ERC-4337 UserOperationEvents across both EntryPoints to determine if it's a smart account, its operation count and success rate, and who sponsors its gas fees (self vs. which paymaster).

## Facts

- Endpoint: GET https://402.com.tr/api/x402/gas-payer
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gas-sponsor-check-cd4f3c7e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WQGpQ9RxdfQi44Ne_cSdP

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 gas-sponsor-check-cd4f3c7e
```

Example prompt: Can you check if the wallet 0xAbC123...def456 is a smart account and find out who's been sponsoring its gas fees over the last 30 days — I want to know the paymaster breakdown and whether it's fully sponsored.

## When to prefer this

Choose this endpoint when you need to determine whether a wallet is a smart account (ERC-4337), who is paying its gas fees, and whether it appears to be app- or agent-operated based on paymaster sponsorship patterns. It is especially useful for counterparty screening, fraud detection, and distinguishing human-operated EOAs from programmatic smart accounts — particularly when native ETH balance heuristics would miss paymaster-subsidized wallets.

## Known failure modes

- Missing wallet parameter returns validation error
- Invalid wallet address format causes a bad request error
- Wallet with no ERC-4337 activity returns empty or zero op count
- Days parameter exceeding 90 is rejected or capped
- Network timeouts when querying both EntryPoints simultaneously
- Non-Base/Ethereum-compatible address may return no results

## How this service works

🆕 A smart account's gas can be paid by a PAYMASTER instead of the account itself — invisible to every 'does this wallet spend ETH' heuristic. Reads a wallet's UserOperationEvents across BOTH EntryPoints (v0.6 + v0.7): is it a smart account, its op count and success rate, and WHO sponsors its gas (self vs which paymaster, per-sponsor share). A fully-sponsored account is typically app- or agent-operated. wallet= required, days= optional (default 30, max 90). Not financial advice.

## Output

Returns whether the wallet is a smart account, its total UserOperation count and success rate across EntryPoint v0.6 and v0.7, and a breakdown of who pays its gas: self-funded vs. each sponsoring paymaster with their per-sponsor share of operations.

## 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": [
      "wallet"
     ],
     "properties": {
      "days": {
       "type": "string",
       "description": "Lookback days (optional)"
      },
      "wallet": {
       "type": "string",
       "description": "Wallet address"
      }
     }
    }
   },
   "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/gas-sponsor-check-cd4f3c7e/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)