Permit (EIP-2612)
Permit (EIP-2612): Gasless Approvals
Permit functionality allows token approvals through signatures instead of transactions, enabling gasless user experiences for DeFi interactions. It’s like signing a check instead of going to the bank.
Permit (EIP-2612) is a token standard that enables gasless approvals through cryptographic signatures rather than on-chain transactions. Users can authorize token spending without paying gas fees, with the actual approval happening when tokens are used.
How Permit Works
Signature-based approvals use cryptographic signatures to authorize token spending without requiring an on-chain transaction for the approval itself.
Deadline enforcement includes expiration times in permit signatures to prevent old authorizations from being used maliciously after extended periods.
Nonce tracking prevents signature replay attacks by ensuring each permit signature can only be used once per wallet.
Real-World Examples
- Uniswap V3 uses permits for gasless approval experiences in token swapping
- 1inch implements permit functionality to reduce transaction steps and costs
- Various DeFi protocols integrate permit to improve user onboarding and experience
Why Beginners Should Care
Better UX eliminates the two-step process of approve-then-spend that traditionally requires two separate transactions and gas payments.
Reduced costs by combining approval and usage into single transactions, cutting gas fees in half for many DeFi operations.
Security considerations require understanding permit signatures and ensuring you trust applications before signing token authorizations.
Related Terms: Token Approval, Gasless Transactions, EIP-2612