Base USDC balance API: ERC-20 token balance of a wallet

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

ERC-20 token balance of a wallet on Base (USDC, USDT, WETH or any token, via balanceOf): raw amount, decimals, symbol and the human-readable amount, live from the token contract. Use to check stablecoin or token holdings before a transfer or trade; for the native coin use base_balance. Both inputs are 0x addresses (40 hex characters); no contract returns 404 and a non-ERC-20 contract 422, both uncharged.

When to use it

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

Token: a ticker such as USDC, USDT, WETH or DAI, or the 0x ERC-20 contract address
0x wallet address

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
token (required)stringToken: a ticker such as USDC, USDT, WETH or DAI, or the 0x ERC-20 contract address
address (required)string0x wallet address

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/base/token-balance?token=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913&address=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/base/token-balance?token=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913&address=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "chain": "Base",
  "chainId": 8453,
  "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "symbol": "USDC",
  "decimals": 6,
  "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "raw": "2500000",
  "balance": "2.5"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is base_token_balance, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

Questions

What if the token address is wrong?

No contract returns 404 and a non-ERC-20 contract 422, both uncharged.

What about ETH itself?

Use base_balance for the native coin.

How do I pay?

Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.

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