Token Approval Checker

WHAT IT DOES

Token Approval Checker is a read-only security tool that examines approval states on EVM-compatible blockchains. It reads ERC-20 allowance (approval) states for specific token-wallet-spender combinations, and checks ERC-721 and ERC-1155 isApprovedForAll status for operators. The tool retrieves current approval states directly from token contracts using the standard allowance() and isApprovedForAll() methods, displaying the exact approved amount or approval status. This helps users identify which contracts have been granted permission to transfer their tokens, enabling informed decisions about security.

HOW TO USE

Select the desired EVM chain from the dropdown menu (Ethereum, Optimism, BSC, Polygon, Fantom, Arbitrum, Avalanche, Linea, zkSync Era, or Base). Enter the wallet address (owner) whose approvals you want to check. Enter the token contract address to examine. Optionally enter a specific spender address to check a single approval; leave blank to see a summary. Click "Check Approvals" to view the current allowance or approval status. For ERC-20 tokens, the tool shows the exact allowance amount in the token's decimals. For ERC-721/ERC-1155 tokens, it shows whether the spender is approved for all tokens.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 to connect to the selected network via either the connected wallet's provider or a public RPC endpoint. It dynamically loads minimal ABI fragments for ERC-20 (allowance, decimals, symbol, name) and ERC-721/ERC-1155 (isApprovedForAll). The tool first validates all addresses using ethers.utils.isAddress and checksum formatting. It then calls the allowance() method for ERC-20 tokens, parsing the returned BigNumber and formatting it using the token's decimals. For non-ERC-20 tokens, it attempts isApprovedForAll() to support NFT approval checking. If no spender is specified, it provides guidance to enter one for specific checks.

WHAT IT CANNOT SEE

This tool cannot revoke approvals—it only reads state. It cannot detect approvals that are set via non-standard methods or proxy contracts that do not expose the standard allowance() or isApprovedForAll() interfaces. It is limited to EVM chains only and cannot check approvals on non-EVM chains. It cannot verify whether an approval was intentionally set by the wallet owner or through a malicious transaction. It also cannot detect approvals that are pending or in mempool. The tool does not check ERC-20 approvals for tokens that use non-standard naming conventions or custom approval logic.

PLEASE NOTE

This tool is EVM only. It supports Ethereum, Optimism, BSC, Polygon, Fant