# ERC-20 Token Allowance Checker

> ERC-20 Token Allowance Checker is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-29).

Scans a wallet's ERC-20 token approvals across major chains, identifying active allowances and flagging unlimited ones so users know what to revoke.

## Facts

- Endpoint: POST https://api.vextorium.com/erc20-aprobaciones-pago?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/erc-20-token-allowance-checker-848fea13
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_INf7yQsQB2MWkYHvtoL1h

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 erc-20-token-allowance-checker-848fea13 -d '<json body>'
```

Example prompt: Can you check what ERC-20 token approvals my wallet 0x9b9B3F22BEBD1e3E528C2759a2ca34cD2e0184A1 has active on Ethereum, and flag any unlimited ones so I know what might need revoking?

## When to prefer this

Choose this endpoint when you need a live, multi-chain scan of a wallet's ERC-20 allowances without running your own node or indexer. It's especially useful pre-revocation workflows, security audits after suspected compromise, or any agent that monitors wallet hygiene. It covers common high-risk spenders (Uniswap routers, Permit2) automatically, so you don't need to enumerate them manually.

## Known failure modes

- Wallet address missing or invalid — request fails with validation error
- Unsupported chain specified — must be one of the 12 supported networks
- Timeout on busy chains — endpoint notes up to ~45s latency; may time out under heavy load
- No approvals found — returns empty aprobaciones array (not an error, just clean wallet)
- Invalid token address in tokens array — may skip or error on that token

## How this service works

Which contracts a wallet has allowed to move its ERC-20 tokens: checks the chain's main tokens (or the ones you pass) over recent blocks plus common spenders (Uniswap routers, Permit2), returning the live allowance and flagging unlimited ones. Find and revoke what you don't use. Usually 2-10 s. On Arbitrum it reads the wallet's full approval history for every token; on other chains the public node can limit how far back it searches (reported in the result).

## Output

Returns a JSON object with the chain name, wallet address, list of active approvals (each with token, spender, and allowance amount), count of tokens reviewed, blocks scanned, total live allowances, and count of unlimited approvals flagged. Empty approvals array means no active allowances found.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "red": {
   "enum": [
    "base",
    "ethereum",
    "arbitrum",
    "optimism",
    "polygon",
    "bnb",
    "avalanche",
    "gnosis",
    "linea",
    "scroll",
    "sonic",
    "unichain"
   ],
   "type": "string",
   "description": "Chain (default base)"
  },
  "tokens": {
   "type": "array",
   "items": {
    "type": "string"
   }
  },
  "wallet": {
   "type": "string"
  },
  "bloques": {
   "type": "integer"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "red": "base",
  "nota": "Revisa los tokens indicados (o los principales de la red) y los gastadores habituales; para revocar usa revocar-aprobacion.",
  "wallet": "0x9b9B3F22BEBD1e3E528C2759a2ca34cD2e0184A1",
  "ilimitadas": 0,
  "aprobaciones": [],
  "tokens_revisados": 5,
  "bloques_revisados": 50000,
  "aprobaciones_vigentes": 0
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/erc-20-token-allowance-checker-848fea13/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.vextorium.com](https://www.zero.xyz/host/api.vextorium.com/llms.txt)