# Wallet Approval Audit Base

> Wallet Approval Audit Base is a paid API for AI agents from ari001.tailb4ac3a.ts.net, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-01).

Returns the current ERC-20 token allowance a spender holds over an owner's wallet on the Base network by calling allowance(owner, spender) on the token contract.

## Facts

- Endpoint: GET https://ari001.tailb4ac3a.ts.net/v1/ventures/ethereum_contract_abi_service/wallet_approval_audit_base?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/wallet-approval-audit-base-f1442983
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6m7ti9rqq_LLYV9LWdDb4

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 wallet-approval-audit-base-f1442983
```

Example prompt: Can you check how many USDC tokens the address 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 is approved to spend on behalf of 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Base?

## When to prefer this

Choose this endpoint when you need a live, on-chain read of an ERC-20 token allowance specifically on the Base network. It is ideal for wallet security audits, pre-transaction approval checks, or DeFi permission monitoring on Base. Prefer it over generic Ethereum mainnet allowance checkers when the user's tokens and contracts are on Base (chain ID 8453).

## Known failure modes

- Invalid address format (not 0x + 40 hex) returns a validation error
- Token contract address that is not a valid ERC-20 returns an error or zero
- Network/RPC timeout causes ok=false with an error message
- Non-existent contract address returns zero allowance or an error
- Missing required query parameters (token, owner, or spender) causes a 400-level error

## How this service works

Base ERC-20 approval check: returns the current allowance a spender holds over an owner's tokens, read live via allowance(owner, spender) on the token contract on Base. Takes token (0x + 40 hex), owner (0x + 40 hex), spender (0x + 40 hex). Query: token (ERC-20 contract, 0x + 40 hex), owner (0x + 40 hex), spender (0x + 40 hex).

## Output

Returns a JSON object with ok (boolean), result (the allowance as a uint256 decimal string — e.g. '115792089237316195423570985008687907853269984665640564039457584007913129639935' for unlimited approval or '0' if revoked), chain (e.g. 'base'), method, service name, and an error string if the call failed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "token",
      "owner",
      "spender"
     ],
     "properties": {
      "owner": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$",
       "description": "0x + 40 hex"
      },
      "token": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$",
       "description": "ERC-20 contract, 0x + 40 hex"
      },
      "spender": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$",
       "description": "0x + 40 hex"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "ok",
      "service"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "chain": {
       "type": "string"
      },
      "error": {
       "type": "string",
       "description": "present when ok is false"
      },
      "method": {
       "type": "string"
      },
      "result": {
       "type": "string",
       "description": "the uint256 as a decimal string"
      },
      "service": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/wallet-approval-audit-base-f1442983/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ari001.tailb4ac3a.ts.net](https://www.zero.xyz/host/ari001.tailb4ac3a.ts.net/llms.txt)