# Xerxes ERC-20 balanceOf

> Xerxes ERC-20 balanceOf is a paid API for AI agents from ari001.tailb4ac3a.ts.net, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-02).

Returns the ERC-20 token balance of a specific wallet address for a given token contract on Ethereum mainnet

## Facts

- Endpoint: GET https://ari001.tailb4ac3a.ts.net/v1/ventures/ethereum_contract_abi_service/erc20_balanceof?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/xerxes-erc-20-balanceof-4d437f6e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Hylp0KruS6GVhO_8cPhAw

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 xerxes-erc-20-balanceof-4d437f6e
```

Example prompt: What's the current USDC balance of the wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on the USDC contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48?

## When to prefer this

Use this endpoint when you need to look up the on-chain ERC-20 token balance for a specific wallet address on Ethereum mainnet. Prefer this over general blockchain explorers when you need a programmatic, machine-readable decimal balance for agent workflows, DeFi logic, access gating, or portfolio tracking.

## Known failure modes

- Invalid ERC-20 contract address format returns a 400 or error response
- Invalid holder address format returns error
- Non-ERC-20 contract address (e.g. EOA or non-standard contract) may return zero or error
- Network issues with Ethereum node cause timeouts
- Contract address that does not implement balanceOf returns an error
- Payment not included or insufficient (x402) results in 402 Payment Required

## How this service works

Returns the ERC-20 token balance of a given address for a specified token contract. Provide token (ERC-20 contract address) and address (holder address). Query: token (ERC-20 contract, 0x + 40 hex), address (holder, 0x + 40 hex).

## Output

A JSON object with 'ok' (boolean success flag), 'result' (the token balance as a uint256 decimal string), 'chain' (the blockchain network), 'service' (service identifier), and on failure an 'error' string describing what went wrong.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "token",
      "address"
     ],
     "properties": {
      "token": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$",
       "description": "ERC-20 contract, 0x + 40 hex"
      },
      "address": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$",
       "description": "holder, 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/xerxes-erc-20-balanceof-4d437f6e/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)