# Base Mainnet Wallet Balance Checker

> Base Mainnet Wallet Balance Checker is a paid API for AI agents from ca-tax-api-mainnet.lxtap.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-23).

Returns the native ETH balance and up to 20 ERC-20 token balances for a given wallet address on Base mainnet, formatted with each token's symbol and decimals.

## Facts

- Endpoint: GET https://ca-tax-api-mainnet.lxtap.workers.dev/base/balances?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-mainnet-wallet-balance-checker-2ed76e1b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PgLsf_z1DCHTVGAQ6ZhED

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-mainnet-wallet-balance-checker-2ed76e1b
```

Example prompt: What's the ETH balance and USDC balance for wallet 0xAbC...123 on Base mainnet? Also check 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 as a token address.

## When to prefer this

Use this endpoint when you need live, formatted ETH and ERC-20 token balances specifically on Base mainnet, supporting up to 20 tokens in a single call with human-readable symbols and decimals. Prefer it over generic RPC calls when you want pre-formatted balances rather than raw hex values, and when you need multi-token portfolio data in one request. For OP Mainnet balances, use the sibling endpoint. For Arbitrum or Polygon, use their respective endpoints.

## Known failure modes

- Invalid or malformed wallet address (not matching 0x + 40 hex chars) returns an error
- More than 20 token contract addresses provided returns a validation error
- Invalid ERC-20 contract address (non-contract or wrong chain) may return zero balance or error
- Network or RPC issues on Base mainnet may cause timeouts
- Missing required 'address' query parameter returns a 400-level error

## How this service works

Pay-per-call data for AI agents, paid in USDC on Base with x402: token risk checks (rug check) on Base, Ethereum, Arbitrum, Optimism, Polygon and Solana, onchain reads (balances, transactions, gas, contracts, NFTs, whale trades, new pools, ENS and Basenames), ECB exchange rates, and Canadian sales tax and business days.

## Output

A structured response containing the wallet's native ETH balance and, for each requested ERC-20 contract address, the token balance formatted with the correct decimal precision alongside the token symbol — all read live from Base mainnet.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "address"
     ],
     "properties": {
      "tokens": {
       "type": "string",
       "pattern": "^(0x[0-9a-fA-F]{40})(,0x[0-9a-fA-F]{40}){0,19}$",
       "description": "Comma-separated ERC-20 contract addresses on Base, up to 20"
      },
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "Wallet address on Base"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": "base",
  "tokens": [
   {
    "raw": "3528717773",
    "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "symbol": "USDC",
    "balance": "3528.717773",
    "decimals": 6
   },
   {
    "raw": "886309838294787826109722",
    "token": "0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed",
    "symbol": "DEGEN",
    "balance": "886309.838294787826109722",
    "decimals": 18
   }
  ],
  "address": "0x2211d1D0020DAEA8039E46Cf1367962070d77DA9",
  "nativeSymbol": "ETH",
  "nativeBalance": "7.554675633166555733"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-mainnet-wallet-balance-checker-2ed76e1b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ca-tax-api-mainnet.lxtap.workers.dev](https://www.zero.xyz/host/ca-tax-api-mainnet.lxtap.workers.dev/llms.txt)