# Base ERC-20 Balance

> Base ERC-20 Balance is a paid API for AI agents from api.arysphere.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-17).

Returns the ERC-20 token balance (balanceOf) for a specific holder address on the Base blockchain

## Facts

- Endpoint: GET https://api.arysphere.com/v1/ventures/x402_chain_reads_v1/base_erc20_balanceof?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-erc-20-balance-8b70cda5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_d-G6Gw9fsUqGmrrgVY1jl

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-erc-20-balance-8b70cda5
```

Example prompt: What's the current token balance of wallet 0xAbCd...1234 for the USDC contract at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base?

## When to prefer this

Use this endpoint when you need to read the ERC-20 token balance of a specific address on the Base L2 network. Prefer this over Ethereum mainnet equivalents when the token is deployed on Base. Choose this over bundle endpoints when you only need a single balanceOf read and want minimal cost. Ideal for lightweight on-chain checks without running your own Base node.

## Known failure modes

- Invalid token address format (not 0x + 40 hex) — returns error or empty
- Invalid holder address format — returns error
- Token contract does not exist on Base — may return zero or error
- Network/RPC issues on Base — timeout or service unavailable
- Rate limiting or payment failure — 402 response if USDC payment not processed

## 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), chain ('base'), method ('balanceOf'), result (the raw token balance as a string integer, in the token's smallest unit), and service identifier. For example: {ok: true, chain: 'base', method: 'balanceOf', result: '70000', service: 'x402_chain_reads_v1.base_erc20_balanceof'}.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "token": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "ERC-20 contract, 0x + 40 hex"
      },
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "holder, 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,
  "chain": "base",
  "method": "balanceOf",
  "result": "70000",
  "service": "x402_chain_reads_v1.base_erc20_balanceof"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-erc-20-balance-8b70cda5/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)