ERC-20 Permit-Based Gasless Approval Tool

WHAT IT DOES

This tool evaluates ERC-20 permit-based gasless approval readiness, helping users determine if a token supports EIP-2612 (permit) and whether a gasless approval is needed or already in place. Given an ERC-20 token contract address, an owner address, a spender address, and an optional requested allowance amount, it reads the token's name, symbol, decimals, total supply, owner balance, spender balance, current allowance, owner nonce, and domain separator. It then determines permit support status—whether the token implements the permit function—and checks if the current allowance is sufficient for the requested amount. The tool displays a clear permit status—Permit valid (allowance sufficient), Permit needed (insufficient allowance), Permit not supported, or No allowance set—along with all relevant token and permit parameters including the domain separator and nonce. All data is pulled directly from the blockchain in real time, providing a transparent, informed view before attempting a gasless approval transaction.

HOW TO USE

Connect your wallet using the Connect button in the header. Select the target network from the dropdown—Ethereum Mainnet, Polygon, Optimism, Arbitrum One, Base, or Sepolia testnet. Enter the ERC-20 token contract address, the owner address (the address giving approval), and the spender address (the address receiving approval). Optionally, enter a requested allowance amount to check if the current allowance is sufficient. Click "Check permit." The tool will fetch the token details, balances, current allowance, nonce, and domain separator. Results appear in the card below with a prominent permit status badge, domain separator details, token information including name, symbol, decimals, total supply, owner and spender balances, current allowance, nonce, and a breakdown of permit readiness factors with checkmarks or crosses. Use this information to determine if a gasless approval via permit is needed or already satisfied.

ERC-20 PERMIT-BASED GASLESS APPROVAL VERIFICATION WITH DOMAIN SEPARATOR AND NONCE ANALYSIS

The tool provides comprehensive ERC-20 permit-based gasless approval verification through multiple on-chain reads. First, it retrieves the token's name, symbol, decimals, total supply, and balances using standard ERC-20 view functions. It then calls allowance() to get the current allowance from the owner to the spender. For EIP-2612 compliance, it calls nonces() to get the owner's current nonce (used for replay protection) and DOMAIN_SEPARATOR() to get the EIP-712 domain separator that defines the signing domain. The domain separator is derived from the token's name, version (typically "1"), chain ID, and the token contract address. The tool also attempts to decode the domain separator components for display. The permit status is determined by checking whether the domain separator exists (indicating permit support) and comparing the current allowance against any requested amount. All factors are combined to provide a clear, actionable permit readiness status with detailed domain and nonce information.

WHAT IT CANNOT SEE

This tool cannot guarantee permit validity—the actual signature may be invalid or expired. It cannot verify off-chain signature authenticity or ensure that the signature was properly generated. It cannot detect signature replay attacks or ensure that the nonce is being used correctly. It cannot ensure gasless transaction success—the permit transaction may fail due to gas issues, network conditions, or contract errors. It cannot assure that the permit contract is free from vulnerabilities, bugs, or malicious code. It cannot verify that the token address is correct or that the owner and spender addresses are valid. It cannot detect front-running or other execution risks. It cannot provide legal or financial advice or guarantee that using the permit function is safe. All data is provided as-is for informational purposes only; any reliance on the tool's output for permit decisions is the sole responsibility of the user.

PLEASE NOTE

This tool supports EVM-compatible chains only: Ethereum Mainnet (1), Polygon (137), Optimism (10), Arbitrum One (42161), Base (8453), and Sepolia testnet (11155111). Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported. The tool requires a Web3 provider (MetaMask or WalletConnect) and access to an RPC endpoint for the selected chain. It does not store any wallet data, token addresses, or permit records. All queries are performed directly against the blockchain in real time. The tool only provides read-only information and does not execute any transactions. Permit support is determined by the presence of the DOMAIN_SEPARATOR and nonces functions and does not guarantee full EIP-2612 compliance. Always verify critical data independently through a block explorer and consult with developers before using permit-based approvals.