# AgentIndex x402 Wallet Balance

> AgentIndex x402 Wallet Balance is a paid API for AI agents from x402.agentindex.world, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-29).

Returns native token (ETH/MATIC/etc.) and USDC balances for any EVM wallet address on supported chains

## Facts

- Endpoint: GET https://x402.agentindex.world/wallet-balance?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentindex-x402-wallet-balance-15d9c86c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_chQQatUXXTDVw9yJrPL30

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 agentindex-x402-wallet-balance-15d9c86c
```

Example prompt: What's the current ETH and USDC balance for wallet address 0xb3F32bdfe8D07825BC0D7387295aB1D7559BA69d on Base?

## When to prefer this

Use this endpoint when an AI agent needs to read live on-chain wallet balances across Base, Ethereum, Polygon, Arbitrum, or Optimism without running its own node. It's ideal for pre-transaction fund checks, portfolio reads, or treasury monitoring, especially within x402/MPP pay-per-call agent workflows where the cost ($0.0001 USDC) is negligible. Prefer this over generic blockchain RPCs when you want a structured JSON response with both native and USDC balances in one call.

## Known failure modes

- Invalid wallet address format (not 0x + 40 hex chars) returns validation error
- Unsupported network name returns enum error
- Payment failure (insufficient USDC for x402 micropayment) blocks the call
- Network RPC unavailability may return timeout or 503
- Address with no on-chain activity returns zero balances but succeeds

## How this service works

Read native coin and USDC balances for any EVM wallet on Base, Ethereum, Polygon, Arbitrum or Optimism, with atomic amounts and current block. No RPC key or account. Try GET /wallet-balance/sample.

## Output

Returns a JSON object containing the wallet address, network metadata (key, name, CAIP-2 identifier), block number at time of query, native token balance (symbol, human-readable balance, and wei amount), and USDC balance (human-readable balance, atomic balance, decimals, and contract address).

## 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",
     "required": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "description": "EVM wallet address (0x followed by 40 hexadecimal characters)."
      },
      "network": {
       "enum": [
        "base",
        "ethereum",
        "polygon",
        "arbitrum",
        "optimism"
       ],
       "type": "string",
       "description": "EVM network to read; aliases and CAIP-2 identifiers are also accepted."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "address",
      "network",
      "block_number",
      "native",
      "usdc"
     ],
     "properties": {
      "usdc": {
       "type": "object"
      },
      "native": {
       "type": "object"
      },
      "address": {
       "type": "string"
      },
      "network": {
       "type": "object"
      },
      "block_number": {
       "type": "integer"
      },
      "x402_receipt": {
       "type": "object"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "usdc": {
   "balance": 1.25,
   "contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "decimals": 6,
   "balance_atomic": "1250000"
  },
  "native": {
   "symbol": "ETH",
   "balance": 0.001,
   "balance_wei": "1000000000000000"
  },
  "address": "0xb3F32bdfe8D07825BC0D7387295aB1D7559BA69d",
  "network": {
   "key": "base",
   "name": "Base",
   "caip2": "eip155:8453"
  },
  "block_number": 51500000
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentindex-x402-wallet-balance-15d9c86c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentindex.world](https://www.zero.xyz/host/x402.agentindex.world/llms.txt)