# Base Chain Address Lookup

> Base Chain Address Lookup is a paid API for AI agents from hubvibe-io.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-27).

Returns ETH balance, transaction count, and account type (contract vs EOA) for a single Base mainnet address in one call

## Facts

- Endpoint: POST https://hubvibe-io.com/work/chain/address?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-chain-address-lookup-88774c1b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eI-xu-Tz7Ge_ydUS3tnCp

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 base-chain-address-lookup-88774c1b -d '<json body>'
```

Example prompt: Can you look up the ETH balance, transaction count, and whether the address 0x742d35Cc6634C0532925a3b844Bc454e4438f44e is a smart contract or a regular wallet on Base mainnet?

## When to prefer this

Choose this endpoint when you need a quick, consolidated snapshot of a Base mainnet address — especially when you need all three data points (balance, tx count, account type) and want to avoid making three separate RPC calls. Ideal for due-diligence checks, wallet validation, and contract-detection workflows where cost ($0.05/call) is acceptable for the convenience of a single aggregated response.

## Known failure modes

- Invalid or malformed address (not 0x-prefixed or wrong length) — likely returns a 400-level error
- Address not found or never used on Base — may return zero values for balance and tx count
- Base RPC node unavailability or timeout — may return 5xx error
- Payment failure or insufficient USDC balance — x402 payment error before the call is processed

## How this service works

Base wallet lookup / address balance: ETH balance, transaction count (nonce) and whether the address is a smart contract or an ordinary wallet (EOA), live from Base mainnet in one call. Use it to check a counterparty, deposit address or contract before paying it. Input: address (0x...). For token balances or any other read use chain.rpc.

## Output

Returns three aggregated chain-read values for the given Base mainnet address: (1) current ETH balance, (2) total transaction count (nonce), and (3) a flag indicating whether the address is a smart contract or an externally owned account (EOA).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "address": {
   "type": "string"
  },
  "language": {
   "type": "string",
   "pattern": "^[A-Za-z]{2,3}(-[A-Za-z0-9]{2,8})*$",
   "maxLength": 35
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "address": "0x837C40E2B4e976f43Ffb4451eE281A00fA9477dd",
   "network": "base-mainnet",
   "balance_eth": 1.25,
   "balance_wei": "1250000000000000000",
   "is_contract": false,
   "code_size_bytes": 0,
   "transaction_count": 42
  },
  "status": "ok",
  "worker": "chain.address",
  "price_usd": 0.05,
  "provenance": {
   "steps": [
    {
     "ms": 640,
     "ok": true,
     "step": "address",
     "provider": "base_rpc"
    }
   ],
   "attempts": 1,
   "elapsed_ms": 660,
   "providers_used": [
    "base_rpc"
   ]
  },
  "receipt_id": "rcpt_9f1c2b3a4d5e6f70",
  "receipt_url": "/work/receipts/rcpt_9f1c2b3a4d5e6f70"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-chain-address-lookup-88774c1b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hubvibe-io.com](https://www.zero.xyz/host/hubvibe-io.com/llms.txt)