# ETH Mainnet ERC-20 Balance

> ETH Mainnet ERC-20 Balance is a paid API for AI agents from ari001.tailb4ac3a.ts.net, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-11).

Reads the raw ERC-20 token balance for a given holder address on Ethereum mainnet by calling the balanceOf function on the token contract.

## Facts

- Endpoint: GET https://ari001.tailb4ac3a.ts.net/v1/ventures/x402_eth_reads_v1/eth_mainnet_erc20_balanceof?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/eth-mainnet-erc-20-balance-dac256b1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mN21GdCDus4ipO0EllPth

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 eth-mainnet-erc-20-balance-dac256b1
```

Example prompt: What's the raw ERC-20 balance of wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 for the USDC token contract 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum mainnet?

## When to prefer this

Use this endpoint when you need to read the ERC-20 token balance for a specific holder on Ethereum mainnet directly from the contract. Prefer this over block explorer APIs when you need trustless, on-chain data without API key management, or when building automated agents that need real-time balance checks. This is a read-only call with no side effects and costs a flat $0.002 USDC per call via x402.

## Known failure modes

- Invalid token address format (not 0x + 40 hex) — request rejected with validation error
- Invalid holder address format (not 0x + 40 hex) — request rejected with validation error
- Non-ERC-20 contract address provided — call may return zero or revert
- Payment not fulfilled — x402 payment of $0.002 USDC required before response is returned
- Ethereum node unavailable or rate-limited — may return 5xx error
- Address with no token holdings returns 0, which is valid not an error

## How this service works

Ethereum mainnet ERC-20 balanceOf. Takes query parameters token (ERC-20 contract, 0x + 40 hex) and address (holder, 0x + 40 hex). Returns the holder's raw token balance read from the contract.

## Output

Returns the raw uint256 token balance of the specified holder address as reported by the ERC-20 contract's balanceOf function on Ethereum mainnet. The value is in the token's smallest unit (e.g. 6 decimals for USDC, 18 for most tokens) and must be divided by the token's decimal factor to get a human-readable amount.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "token": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "ERC-20 contract, 0x + 40 hex"
      },
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "holder, 0x + 40 hex"
      }
     }
    }
   },
   "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/eth-mainnet-erc-20-balance-dac256b1/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)