# Base ETH Balance Lookup (eth_getBalance)

> Base ETH Balance Lookup (eth_getBalance) is a paid API for AI agents from api.arysphere.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-17).

Returns the native ETH balance of a Base network address by calling eth_getBalance on-chain.

## Facts

- Endpoint: GET https://api.arysphere.com/v1/ventures/x402_chain_reads_v1/base_eth_getbalance?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-eth-balance-lookup-eth-getbalance-3fae61ce
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_A1gV4g-70Fen5rolvg5rV

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-eth-balance-lookup-eth-getbalance-3fae61ce
```

Example prompt: What's the current ETH balance of the Base address 0xAbCd1234...5678 right now?

## When to prefer this

Use this endpoint when you need the native ETH balance on the Base L2 network specifically — not Ethereum mainnet. Choose this over general RPC calls when you want a simple, paid, no-infrastructure REST interface to Base on-chain data without setting up your own node or managing RPC keys.

## Known failure modes

- Invalid or malformed address (not matching 0x + 40 hex pattern) returns a validation error
- Address not found or never used returns balance of 0 (not an error)
- Network/RPC node unavailability causes timeout or 5xx error
- Payment failure (x402 protocol) if USDC balance is insufficient

## How this service works

ARYSPHERE sells AI-written verdicts on Base token contracts (a grade, a one-liner, a roast and the contract's facts) and Base/Ethereum chain reads, paid per call in USDC on Base over x402 v2. No account and no API key.

## Output

A JSON object containing: 'ok' (boolean success flag), 'result' (native ETH balance as a decimal integer in wei), 'hex' (balance in hexadecimal), 'chain' ('base'), 'method' ('eth_getBalance'), and 'service' identifier. A zero balance returns result: 0 and hex: '0x0'.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "0x + 40 hex"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "hex": "0x0",
  "chain": "base",
  "method": "eth_getBalance",
  "result": 0,
  "service": "x402_chain_reads_v1.base_eth_getbalance"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-eth-balance-lookup-eth-getbalance-3fae61ce/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.arysphere.com](https://www.zero.xyz/host/api.arysphere.com/llms.txt)