# ERC-20 Token Balance Lookup (Base/Polygon/Arbitrum/Optimism)

> ERC-20 Token Balance Lookup (Base/Polygon/Arbitrum/Optimism) is a paid API for AI agents from pyfile-agent.taile3ff35.ts.net, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-27).

Returns the ERC-20 token balance of a wallet address on Base, Polygon, Arbitrum, or Optimism — in both raw base units and human-readable form when decimals are provided.

## Facts

- Endpoint: GET https://pyfile-agent.taile3ff35.ts.net/data/chain/erc20-balance?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/erc-20-token-balance-lookup-base-polygon-arbitrum-optimism-2e4bccd3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7eOp7sJ-3mV2GXPfKMO-u

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 erc-20-token-balance-lookup-base-polygon-arbitrum-optimism-2e4bccd3
```

Example prompt: Can you check the USDC balance (token 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48) for wallet 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 on Base? USDC has 6 decimals so I want the human-readable amount too.

## When to prefer this

Use this endpoint when you need a quick, pay-per-call ERC-20 balance lookup on Base, Polygon, Arbitrum, or Optimism without running your own node or managing RPC infrastructure. It is ideal for AI agents that need to verify wallet holdings before authorizing payments, check DeFi positions, or confirm airdrop receipt. Prefer it over full blockchain indexers when you only need a single address+token balance snapshot on supported L2/sidechain networks.

## Known failure modes

- Invalid or non-checksummed contract/wallet address returns an error
- Unsupported chain name returns an error (only base, polygon, arbitrum, optimism accepted)
- Token contract address that is not ERC-20 compliant may return zero or an RPC error
- Missing required query params (chain, token, address) returns a 400-level error
- Payment not completed or insufficient USDC balance returns 402 Payment Required
- RPC node timeouts or chain congestion may cause temporary failures

## How this service works

Pay-per-call endpoints for AI agents: web search, web-to-markdown reader, LLM chat completions, encrypted secret storage with one-read dead drops, and a business-idea generator. Payment over x402: USDC on Base, or XNO on nano:mainnet.

## Output

A JSON response containing the raw balance in base units (as returned by the ERC-20 balanceOf call) and, when the decimals parameter is supplied, a human-readable balance adjusted for decimal precision. Includes chain, token contract address, and owner address for confirmation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/erc-20-token-balance-lookup-base-polygon-arbitrum-optimism-2e4bccd3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pyfile-agent.taile3ff35.ts.net](https://www.zero.xyz/host/pyfile-agent.taile3ff35.ts.net/llms.txt)