# x402 Wallet Balance Lookup

> x402 Wallet Balance Lookup is a paid API for AI agents from x402tap.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-13).

Returns native token (ETH/MATIC/etc.) and optional ERC-20 token balances for a wallet address on major EVM chains

## Facts

- Endpoint: GET https://x402tap.com/api/wallet-balance?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-wallet-balance-lookup-b193239e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bQ9hxfg59lUqlAAolxmyv

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 x402-wallet-balance-lookup-b193239e
```

Example prompt: What's the ETH balance and USDC token balance for wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Base?

## When to prefer this

Choose this endpoint when you need on-chain wallet balance data across Base, Ethereum, Polygon, Arbitrum, or Optimism in a single call, especially when you also want ERC-20 token balances alongside native balances. It's ideal for agents that need to verify wallet liquidity, check holdings before executing transactions, or enrich user portfolio views. The x402 micropayment model makes it cost-effective for high-frequency per-address lookups.

## Known failure modes

- Invalid or malformed wallet address returns an error response
- Unsupported chain name causes a 400 or error response
- Invalid ERC-20 token contract address returns null or error for the token field
- Network/RPC issues for a specific chain may cause timeouts
- Payment failure (402) if USDC balance is insufficient for the $0.002 call fee

## How this service works

Native and (optional) ERC-20 token balance for a wallet address across major EVM chains (base, ethereum, polygon, arbitrum, optimism)

## Output

A JSON object containing the wallet address, the chain name, the native token symbol and balance (e.g. ETH: 1.24), and — if an ERC-20 contract was specified — the token symbol, contract address, decimal precision, and formatted token balance (e.g. USDC: 500.0).

## 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": "Chain to query: base, ethereum, polygon, arbitrum, optimism (default base)"
      },
      "token": {
       "type": "string",
       "description": "Optional ERC-20 token contract address to also check"
      },
      "address": {
       "type": "string",
       "description": "EVM wallet address (0x...)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": "Base",
  "token": {
   "symbol": "USDC",
   "address": "0x8335...",
   "balance": "500.0",
   "decimals": 6
  },
  "native": {
   "symbol": "ETH",
   "balance": "1.24031"
  },
  "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-wallet-balance-lookup-b193239e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402tap.com](https://www.zero.xyz/host/x402tap.com/llms.txt)