What an allowance is

A token contract can record a standing permission from your address to another address. That record is an allowance. While it exists, the spender can move up to that amount without asking you again.

Every swap, mint, or deposit you have ever signed created one. That is not a flaw — it is how the transaction avoids asking you twice. The permission simply stays behind after the original action is finished.

Why an unlimited approval is a risk

Most interfaces request the maximum possible amount, so the allowance reads as unlimited. Three things follow from that:

• The permission does not expire. It remains until it is set to zero.
• If the spender contract is later upgraded, the same permission applies to the new code.
• If the spender is one you no longer use, the permission outlives your use of it.

How a revocation works

Revoking means setting the recorded allowance back to zero. There are two ways a wallet can do that:

Method	Gas	You sign
On-chain transaction	You pay	A transaction
Signed message	None	A signature

This scanner uses the second. One signature covers the whole selected set, so a batch of approvals is cleared in a single confirmation rather than one transaction each.

What the scan reads

Three read-only calls per token contract, none of which require permission:

balanceOf(your address)	how much you hold
allowance(you, spender)	how much they may move
decimals()	how to display the amount

These are reads against the public chain state. They cost nothing, change nothing, and are the reason no signature is requested until you choose to revoke.

Known limitations

Stated plainly, because a tool that claims no limits is not worth trusting:

• Token list, not every token. The scan checks a curated set of the highest-liquidity contracts per network. A long-tail token holding an approval will not appear.
• Four networks. Base, Ethereum, Arbitrum and BNB. Approvals on other chains are not read.
• Native balance is separate. A native balance has no allowance mechanism, so it is handled by a distinct protection step rather than the approval list.
• Small balances are skipped. Below roughly one dollar, the cost of clearing exceeds the exposure.
• Hardware wallets. A device can show detail the summary does not, and may refuse the signature entirely.

Safety

If any page asks you to type twelve words, it is not this one. The two are easy to confuse and the difference is total: a signature can be limited to a single action, a seed phrase cannot.

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