# presign-guard ERC-20 Approval Auditor

> presign-guard ERC-20 Approval Auditor is a paid API for AI agents from presign-guard.fizzl.eu, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-11).

Audits all open ERC-20 token allowances for an EVM wallet, grading each approval and identifying risky, unlimited, or flagged spenders to revoke

## Facts

- Endpoint: GET https://presign-guard.fizzl.eu/v1/approvals?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/presign-guard-erc-20-approval-auditor-da143827
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_AvpIUjWVo2tTQkNT7E-l3

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 presign-guard-erc-20-approval-auditor-da143827
```

Example prompt: Can you audit all the ERC-20 approvals on my Ethereum wallet 0xAbC1234... and tell me which ones are risky, unlimited, or should be revoked?

## When to prefer this

Choose this endpoint when you need a comprehensive, structured audit of all ERC-20 allowances for a specific EVM wallet, especially when you want spender classification (flagged, unlimited, unverified), a clear risk grade, and actionable revocation recommendations. It covers six major EVM chains in a single call. Prefer this over generic blockchain explorers when you need machine-readable risk grades and pre-classified spender data rather than raw on-chain data. Ideal for AI agents automating wallet hygiene, post-incident triage, or pre-protocol due diligence.

## Known failure modes

- Invalid wallet address format returns an error — address must be a valid 0x EVM address
- Unsupported chain value returns an enum validation error — must be base, ethereum, arbitrum, optimism, polygon, or bsc
- Payment not received or insufficient USDC balance causes a 402 payment required error
- Wallet with no on-chain history or approvals returns an empty approvals list with a SAFE grade
- RPC or chain provider downtime may cause timeout or partial results
- Malformed query parameters return a 400 bad request

## How this service works

Wallet approval audit (green/orange/red, grade, one-line summary): every open ERC-20 allowance of an EVM wallet with who the spender is (flagged, plain wallet, unverified, unlimited) and which ones to revoke. Bulk: 100 checks for $0.80 via /v1/credits.

## Output

Returns a structured audit with: an overall verdict (green/orange/red), a safety grade (SAFE/CAUTION/RISKY/AVOID), a one-line summary, a list of flagged reason codes with severity levels, and a detailed breakdown of every open ERC-20 allowance including spender address, spender classification (flagged/plain wallet/unverified/unlimited), and revocation recommendations. Also includes a signed receipt for payment verification.

## 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"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "chain",
      "address"
     ],
     "properties": {
      "chain": {
       "enum": [
        "base",
        "ethereum",
        "arbitrum",
        "optimism",
        "polygon",
        "bsc"
       ],
       "type": "string",
       "description": "EVM chain to audit"
      },
      "address": {
       "type": "string",
       "description": "Wallet address (0x...)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "verdict",
      "grade",
      "one_liner",
      "reasons",
      "approvals"
     ],
     "properties": {
      "grade": {
       "enum": [
        "SAFE",
        "CAUTION",
        "RISKY",
        "AVOID"
       ],
       "type": "string"
      },
      "reasons": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "code",
         "severity"
        ],
        "properties": {
         "code": {
          "type": "string"
         },
         "details": {},
         "severity": {
          "enum": [
           "red",
           "orange",
           "info"
          ],
          "type": "string"
         }
        }
       }
      },
      "receipt": {
       "type": "object",
       "required": [
        "request_id",
        "route",
        "input_sha256",
        "signed_at",
        "signer",
        "algorithm",
        "signature"
       ],
       "properties": {
        "cert": {
         "type": "object",
         "properties": {
          "signer": {
           "type": "string"
          },
          "service": {
           "type": "string"
          },
          "authority": {
           "type": "string"
          },
          "signature": {
           "type": "string"
          },
          "valid_from": {
           "type": "string"
          }
         },
         "description": "The payout wallet's certificate for this signing key:
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/presign-guard-erc-20-approval-auditor-da143827/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from presign-guard.fizzl.eu](https://www.zero.xyz/host/presign-guard.fizzl.eu/llms.txt)