EIP-712 & ERC-2612 Cryptography · Gasless Checkout QA

ERC-2612 Gasless Permit & EIP-712 Inspector.

Generate exact eth_signTypedData_v4 EIP-712 domain separators, integer base-unit values, deadline windows, and relayer execution estimates for USDC, EURC, PYUSD, and DAI across XPayr's gasless-ready EVM networks.

⚡ Gasless Permit Hub 🛡️ Fee Delegation Proof 🔬 99.5% / 0.5% Split Visualizer 🌐 All 16 Networks

1. Configure Token, Chain & Invoice Parameters

2. EIP-712 TypedData & Non-Custodial Split

Buyer Native Gas Required $0.00 (Off-Chain Signature)
Relayer /Sponsored Gas Est. ~$0.004
Merchant Net (99.5% Atomic) 119.40 USDC
Permit Standard & Version EIP-2612 · v2
eth_signTypedData_v4 Payload JSON 

        

    


    

        

            FAQ
            
Questions about ERC-2612 Gasless Permit & EIP-712

        

        

                            

                    
What problem does ERC-2612 Gasless Permit solve at crypto checkout?

                    
Over 30% of retail Web3 buyers hold USDC or EURC on Base, Arbitrum, or Polygon with $0.00 in native ETH or POL gas. ERC-2612 lets the buyer sign a free off-chain EIP-712 Permit message while XPayr Fee Delegation or Circle Arc USDC-native gas executes the atomic 99.5% / 0.5% settlement (/gasless).

                

                            

                    
Why does EIP-712 domain version differ across USDC, EURC, PYUSD, and DAI?

                    
Circle FiatTokenV2_2 (native USDC and EURC) uses EIP-712 version "2", whereas PYUSD and standard OpenZeppelin ERC20Permit contracts typically use version "1". Passing the wrong version invalidates ecrecover on-chain — which is why this inspector outputs the exact canonical domain metadata per chain and asset.

                

                            

                    
Does signing an ERC-2612 Permit give XPayr custody of the buyer wallet?

                    
Never. Every XPayr Permit payload is strictly scoped to the exact invoice amount (value), a short session expiration (deadline), a single-use wallet nonce, and the audited XPayr non-custodial router contract (/trust/fee-delegation).

                

                            

                    
What happens if a buyer selects USDT or a non-EVM chain without ERC-2612?

                    
XPayr Dual Checkout automatically detects token capability and falls back gracefully to standard 1-Click Web3 transfer or Direct Exchange QR (/trust/fee-delegation) so checkout never breaks.