EIP-2612: How ERC-20 Enables Gasless Approvals

Gas fees are the biggest source of friction in DeFi. Before you can swap, lend, or stake an ERC‑20 token, you often need to submit an “approve” transaction—and pay gas—just to let the dApp move your tokens. EIP‑2612 changes that. It introduces “permit,” a signature-based approval flow that moves the approval off-chain and lets a smart contract or relayer sponsor the gas on-chain. The result is smoother UX, fewer transactions, and safer approvals when implemented correctly.

This article explains how EIP‑2612 works, why it matters in 2025, and what users and developers should watch out for.

What EIP‑2612 Actually Is

EIP‑2612 extends the ERC‑20 token standard with a new function: permit. Instead of calling approve(spender, amount) on-chain, users sign a typed message off-chain that includes the approval parameters and a deadline. A smart contract then submits permit on-chain using that signature, setting the allowance without the user paying gas.

• ERC‑20 basics: approvals and transfers follow the standard defined in the ERC‑20 specification.
• EIP‑2612 spec: the signature format, nonces, and the permit function are formalized in the EIP‑2612 proposal.
• Typed data: signatures use structured data per EIP‑712, which makes what you’re signing human-readable and domain-bound.

In short, EIP‑2612 allows “gasless approvals” because the user only signs off-chain; a dApp, relayer, or contract pays to relay the permit on-chain.

Why It Matters in 2025

• Fewer clicks, fewer transactions: One signature can set approval and immediately execute an action (swap, deposit, stake) in a single on-chain call.
• L2-first UX: With L2s thriving, many protocols sponsor gas to onboard users. EIP‑2612 approvals fit neatly into those patterns. See Ethereum’s overview of gas and account models to understand the cost dynamics.
• Account abstraction and paymasters: Wallet flows powered by ERC‑4337 make it easier for services to sponsor gas or accept fees in tokens. EIP‑2612 complements these UX improvements: you approve via signature, and your transaction can be sponsored.
• Forward-looking protocol changes: Discussions around wallet-native authorization like EIP‑3074 and EIP‑7702 highlight a broader trend toward signature-driven operations. Even as those evolve, EIP‑2612 remains a practical, widely deployed tool for approvals today.

How Gasless Approvals Work (Step-by-Step)

1. You initiate an action (e.g., swap a token) in a dApp.
2. The dApp prepares an EIP‑712 typed message with fields: owner, spender, value, nonce, deadline, and token’s domain separator (name, version, chainId, contract address).
3. You sign the message with your wallet, approving exact parameters.
4. The dApp or relayer submits permit(owner, spender, value, deadline, v, r, s) on-chain and, in the same transaction, calls the dApp action that uses the allowance.
5. The token contract verifies the signature, checks the nonce and deadline, then sets the allowance.

The key idea: you don’t pay gas for the approval. You only sign.

Native Permit vs. Permit2

Not all tokens implement EIP‑2612. To solve fragmented interfaces and improve safety, Uniswap introduced Permit2—a generalized approval system that standardizes signature approvals and allowance management across tokens.

• Permit2 overview and reference implementation: Uniswap Permit2

When a token supports native permit, dApps can use it directly. When it doesn’t, Permit2 provides a consistent interface while restricting allowances to the Permit2 contract, often improving control and revocation UX.

Security Considerations You Should Care About

Gasless does not mean riskless. Signatures are powerful; treat them like transactions.

• Verify the spender: Always check which contract will get the allowance. EIP‑712 typed data should show the spender address clearly. Learn how typed data works in EIP‑712.
• Limit the amount and set a sensible deadline: Avoid unlimited approvals unless you trust the protocol deeply. Deadlines reduce the attack window.
• Check chainId and domain: Signatures are valid only on the intended network and token contract via the domain separator. Beware of cross-chain replay attempts or phishing.
• Manage nonces: EIP‑2612 uses nonces to prevent replay. Rely on reputable token implementations, ideally audited and using well-tested libraries such as OpenZeppelin’s ERC20Permit.
• Revoke allowances: Regularly review and revoke unused approvals in your wallet interface or via the token contract.
• Meta-transaction trust: If a relayer submits your permit, ensure you trust the dApp’s backend. For meta-transaction patterns, see EIP‑2771 (Trusted Forwarder).

Good implementations help mitigate issues, but user vigilance is essential. For general best practices, OpenZeppelin’s documentation is a solid starting point: OpenZeppelin Contracts.

Developer Notes: Implementing and Using Permit

• Use a battle-tested implementation: OpenZeppelin’s ERC20Permit and draft-EIP712 reduce footguns and stay aligned with the spec. Reference: ERC20Permit.
• Bundle execution: Design your dApp to accept a permit signature and perform the action in the same transaction for one-click UX.
• Support both flows: Prefer native permit when available; fall back to Permit2 if the token lacks it. Reference: Uniswap Permit2.
• Handle deadlines and nonces robustly: Reject expired signatures and confirm the expected nonce before submitting on-chain.
• Consider sponsorship: Combine EIP‑2612 with ERC‑4337 paymasters to create truly seamless, sponsored flows. Reference: ERC‑4337.

Common Questions

• Is this “free”?
  The user doesn’t pay gas for the approval; someone else does. The dApp may still charge fees via its smart contract logic.

• What if a token doesn’t support EIP‑2612?
  Use Permit2, or fall back to a standard approve flow with clear UX prompting.

• Does permit work across chains?
  No. Signatures are scoped via EIP‑712 to a domain (token contract + chainId). You must sign for the specific network.

• Are hardware wallets compatible?
  Any wallet that supports EIP‑712 typed data can render permit messages. Good wallets show spender, amount, and deadline clearly.

Final Thoughts

EIP‑2612 is one of those small but pivotal improvements that makes DeFi feel instant. By turning approvals into signatures, it removes a common UX hurdle and pairs naturally with modern flows on L2s and account abstraction.

If you rely on permit-based workflows, choose a wallet that renders EIP‑712 messages transparently and keeps keys offline. OneKey hardware wallets focus on clear, on-device EIP‑712 previews (spender, amount, deadline, chain), open-source firmware, and broad EVM/L2 support—useful when you want the convenience of gasless approvals without compromising on signature safety.