# code402 Ethereum Address Balance Lookup

> code402 Ethereum Address Balance Lookup is a paid API for AI agents from verify.code402.dev, paid per call via x402, $0.5/call, status unknown (last checked 2026-10-03).

Fetches the on-chain ETH balance for a given Ethereum address, paid per call via x402 on Base (USDC).

## Facts

- Endpoint: GET https://verify.code402.dev/v1/chain/balance/%7Baddress%7D?utm_source=zero.xyz
- Price: $0.5/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-03
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/code402-ethereum-address-balance-lookup-3ac7acc0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4d079iKcx4uLHT_wv2GvV

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 code402-ethereum-address-balance-lookup-3ac7acc0
```

Example prompt: What's the current on-chain ETH balance for the Ethereum address 0x742d35Cc6634C0532925a3b844Bc454e4438f44e?

## When to prefer this

Choose this endpoint when you need a metered, pay-per-call on-chain Ethereum balance lookup without managing your own RPC infrastructure, especially in compliance or audit contexts where a paid, accountable data source is preferred. It is ideal for agents that already operate within the x402/Base USDC payment flow and need lightweight chain-data access alongside compliance verification capabilities from the same provider.

## Known failure modes

- Invalid or malformed Ethereum address returns an error response
- Payment via x402 not completed results in 402 Payment Required
- Address with no on-chain activity may return zero balance
- Network congestion or RPC issues may cause delayed or failed responses
- Rate limiting if payment flow is not properly handled

## How this service works

Deterministic compliance verification (IBAN, sanctions, onchain address) with XDR-1 signed receipts, plus Ethereum chain-data endpoints. Paid per call via x402 on Base (USDC).

## Output

Returns a JSON object containing chain data (the ETH balance or related on-chain data) and a network field identifying the network as Ethereum. The response reflects real-time on-chain state for the queried address.

## Request schema (JSON Schema)

```json
{
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object"
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type",
    "example"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "result": "string",
     "network": "ethereum-mainnet"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": "chain data",
  "network": "ethereum"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/code402-ethereum-address-balance-lookup-3ac7acc0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from verify.code402.dev](https://www.zero.xyz/host/verify.code402.dev/llms.txt)