# Base Chain Wallet Balance Lookup

> Base Chain Wallet Balance Lookup is a paid API for AI agents from kr-x402-mvp.kgy5612.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).

Returns the current ETH balance (in both ETH and Wei), nonce, and block number for a given wallet address on the Base network, paid via x402 USDC microtransaction.

## Facts

- Endpoint: GET https://kr-x402-mvp.kgy5612.workers.dev/api/chain/balance?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-chain-wallet-balance-lookup-46c3b1be
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mLFAE25Q90tp-tl_GDTAm

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-wallet-balance-lookup-46c3b1be
```

Example prompt: What's the current ETH balance on Base for wallet 0xe4be4d0bd82d8e68203deff81f79ede0529f2617? I need the balance in both ETH and Wei along with the nonce.

## When to prefer this

Choose this endpoint when your agent needs a lightweight, no-API-key balance lookup for a specific Base wallet address and is already operating in an x402 USDC micropayment context. Ideal for DeFi trading bots, portfolio trackers, or pre-transaction gas checks that need real-time Base chain data without managing API credentials.

## Known failure modes

- Invalid wallet address format (not matching 0x + 40 hex chars) returns a validation error
- Wallet address not found or zero-balance wallet returns balance_eth: 0 and balance_wei: '0' (valid response, not an error)
- x402 payment failure if the agent's USDC balance on Base is insufficient
- Network/RPC timeout on Base may return a 5xx error
- Malformed query param key returns 400 bad request

## How this service works

Pay-per-call crypto microdata for trading/onchain AI agents via x402 (USDC on Base): Base gas, token risk, balances, multi-venue prices, Hyperliquid book/funding, kimchi premium. No API keys.

## Output

Returns a JSON object with the wallet's ETH balance as a decimal float, balance in Wei as a string, current nonce, the Base chain identifier, and the latest block number at time of query.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "wallet"
     ],
     "properties": {
      "wallet": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "examples": [
        "0xe4be4d0bd82d8e68203deff81f79ede0529f2617"
       ],
       "description": "Wallet"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "block": 53204016,
  "chain": "base",
  "nonce": 0,
  "wallet": "0xe4be4d0bd82d8e68203deff81f79ede0529f2617",
  "balance_eth": 0,
  "balance_wei": "0"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-chain-wallet-balance-lookup-46c3b1be/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from kr-x402-mvp.kgy5612.workers.dev](https://www.zero.xyz/host/kr-x402-mvp.kgy5612.workers.dev/llms.txt)