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Base Toolbox – ERC-20 Allowance Checker
x402
Base Toolbox – ERC-20 Allowance Checker is a paid API for AI agents from basetoolbox.cartonpliant.workers.dev, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).
Returns leftover ERC-20 token allowances on Base for a given wallet, listing spenders and suggested next actions like revoking
Price / call$0.1
Success—
StatusUnknown
How this service works
Base toolbox: before you sign on Base — Uniswap v3 preflight, leftover allowances, tx explain, transfer check. $0.10 USDC. Also $0.001 price/gas/ENS. GET /v1/constants free. No CoinGecko key.
Output
Returns a JSON object with an 'ok' boolean, a recommended 'next' action (e.g. 'revoke'), a numeric 'leftover' allowance amount, and an array of 'spenders' with their associated allowance details — giving a clear picture of which contracts have permission to spend tokens from the wallet.
Example use cases
Pre-trade allowance audit on Base
“I'm about to do a Uniswap v3 swap on Base — can you check wallet 0xDEAD...BEEF for any open ERC-20 allowances and flag anything I should revoke before I sign?”
Routine DeFi wallet security review
“Can you scan my Base wallet 0x1234...ABCD for stale token approvals and tell me which spender contracts still have leftover allowances I haven't used?”
Post-hack allowance sweep
“I think my wallet 0x9999...FFFF may have been phished — can you pull all current ERC-20 allowances on Base so I know which spenders to revoke immediately?”
Technical details
Endpoint
POSThttps://basetoolbox.cartonpliant.workers.dev/v1/allowancesWhen to prefer
Use this endpoint when you need a quick, cheap ($0.10 USDC) on-chain lookup of ERC-20 allowances specifically on the Base network — ideal as a preflight check before signing DeFi transactions, auditing wallet exposure, or building revoke-suggestion workflows. Prefer this over building your own RPC calls when you want structured output with actionable recommendations already included.
Side effects
- Invalid or malformed wallet address returns an error
- Token contract not found on Base returns empty or error response
- Network congestion on Base may cause timeout
- Missing required input fields returns a 400-level error
- Payment of $0.10 USDC not provided results in 402 Payment Required
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| input | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"next": "revoke",
"leftover": 1,
"spenders": []
}
}Tags
x402
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