# On-Chain ETH Balance Lookup

> On-Chain ETH Balance Lookup is a paid API for AI agents from store.agentexchange.work, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Returns the native ETH balance, transaction count, and USD value for a given wallet address on EVM-compatible chains

## Facts

- Endpoint: GET https://store.agentexchange.work/chain/balance
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/on-chain-eth-balance-lookup-08b1e63f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4AXibgaY_bPcgafi9aBXh

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 on-chain-eth-balance-lookup-08b1e63f
```

Example prompt: What's the ETH balance and current USD value of the wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on the Base network?

## When to prefer this

Choose this endpoint when you need a lightweight, key-free, pay-per-call lookup of native ETH (or EVM-chain) balance and USD value for any wallet address. Ideal for AI agents that need on-chain reads without managing API keys or subscriptions, especially on Base, Ethereum, Optimism, Arbitrum, Polygon, or Gnosis.

## Known failure modes

- Missing or malformed address (non-0x format) returns 400 error
- Unsupported chain identifier returns an error or defaults to base
- Address with no activity may return zero balances
- Payment not received (402 Payment Required) if x402 USDC payment is not included
- RPC node timeout or chain congestion may cause delayed or failed response

## How this service works

The cheapest on-chain RPC read: any address's native coin balance (ETH/POL/xDAI) with live USD value and outgoing transaction count (nonce), across Base, Ethereum, Optimism, Arbitrum, Polygon, Gnosis. The high-frequency balance check wallet-tracking, settlement, and trading agents poll constantly. Free upstream (Blockscout); undercuts onesource.

## Output

A JSON object containing the chain name, native token symbol (e.g. ETH), the queried wallet address, the raw token balance as a number, total transaction count, and current USD equivalent value of the holdings.

## 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": [
      "address"
     ],
     "properties": {
      "chain": {
       "type": "string",
       "description": "base|ethereum|optimism|arbitrum|polygon|gnosis (default base)"
      },
      "address": {
       "type": "string",
       "description": "Account address (0x...)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "balance": {
       "type": "number"
      },
      "tx_count": {
       "type": "number"
      },
      "usd_value": {
       "type": "number"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/on-chain-eth-balance-lookup-08b1e63f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from store.agentexchange.work](https://www.zero.xyz/host/store.agentexchange.work/llms.txt)