# ERC20 Token Balance for One Holder

> ERC20 Token Balance for One Holder is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-01).

Returns the ERC20 token balance of a specific wallet address for a given token contract on a supported EVM chain

## Facts

- Endpoint: POST https://twin.unykorn.org/erc20-balance?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/erc20-token-balance-for-one-holder-9917d044
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wwb9A1euCXYImS85H0v3f

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 erc20-token-balance-for-one-holder-9917d044 -d '<json body>'
```

Example prompt: What's the USDC balance for wallet 0xAbC1234567890abcdef1234567890abcdef1234 on Base — the USDC contract is 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48?

## When to prefer this

Use this endpoint when you need a fast, on-demand ERC20 token balance lookup for a single wallet-contract pair on any of 10 major EVM-compatible chains (Ethereum, Base, Polygon, Arbitrum, Optimism, BSC, Avalanche, Gnosis, Linea, Scroll). Prefer it over raw RPC calls or broader portfolio APIs when you want a simple pay-per-call model with no API key setup, especially in agent workflows that need to verify token holdings, check DeFi positions, or audit wallet state programmatically.

## Known failure modes

- Invalid owner or contract address format (must match 0x[40 hex chars] pattern)
- Unsupported chain name outside the allowed enum values
- Token contract does not exist on the specified chain
- Network or RPC node connectivity issues causing delayed or failed response
- Insufficient payment causing 402 rejection before data is returned

## How this service works

ERC20 token balance for one holder — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object with ok status, balance details, and a payment receipt including transaction hash, USD amount charged, and a unique receipt ID, along with an ISO8601 timestamp of when the data was generated.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "chain": {
     "enum": [
      "ethereum",
      "base",
      "polygon",
      "arbitrum",
      "optimism",
      "bsc",
      "avalanche",
      "gnosis",
      "linea",
      "scroll"
     ],
     "type": "string"
    },
    "owner": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]{40}$"
    },
    "contract": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]{40}$"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "erc20-balance",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.003,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/erc20-token-balance-for-one-holder-9917d044/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)