# ERC-20 Token Balance

> ERC-20 Token Balance is a paid API for AI agents from www.x402financialdata.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).

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

## Facts

- Endpoint: GET https://www.x402financialdata.com/token-balance/:address
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/erc-20-token-balance-2b2804be
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DrKJNHmrCIggp57IDhZH8

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-balance-2b2804be
```

Example prompt: What's the raw USDC balance (in the smallest unit) for Ethereum wallet 0xAbCd...1234 on the USDC contract 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48?

## When to prefer this

Use this endpoint when you need the on-chain ERC-20 token balance for a specific wallet-contract pair on Ethereum mainnet and you already know both the wallet address and the token contract address. It is more targeted than a multi-token portfolio endpoint when you only need a single token's balance. Prefer this over native ETH balance endpoints when querying ERC-20 tokens. Note that you will need to handle decimal conversion separately since this endpoint returns only the raw smallest-unit value.

## Known failure modes

- Invalid or malformed wallet address returns an error
- Invalid or non-ERC-20 contract address returns an error or zero balance
- Contract address is for a non-Ethereum chain — only 'eth' is supported
- Wallet address has never interacted with the token — returns zero balance (not an error)
- Etherscan API downtime or rate limiting causes 5xx or timeout
- Payment failure (insufficient USDC) blocks the call

## How this service works

ERC-20 token balance for a wallet against one token contract, on Ethereum, from Etherscan's V2 API. Requires contract_address as a query param. Returns the raw balance in the token's smallest unit (decimals aren't included in this endpoint's response). $0.01/call.

## Output

Returns the raw token balance as an integer string in the token's smallest unit (e.g. wei-equivalent for that token). Token decimals are not included, so the calling agent must separately know the token's decimal precision to convert to 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"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "description": "EVM wallet address"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "required": [
      "contract_address"
     ],
     "properties": {
      "chain": {
       "enum": [
        "eth"
       ],
       "type": "string",
       "description": "Which chain to query. Only 'eth' is supported right now."
      },
      "contract_address": {
       "type": "string",
       "description": "ERC-20 token contract address to check the balance of."
      }
     }
    }
   },
   "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/erc-20-token-balance-2b2804be/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from www.x402financialdata.com](https://www.zero.xyz/host/www.x402financialdata.com/llms.txt)