Abstract
EIP-8090 introduces a relayer-protected gasless swap pattern optimised for Uniswap V4 periphery contracts. The mechanism enforces that every gasless swap involves at least one stablecoin leg, automatically burns a configurable percentage fee (default 1%) of the stablecoin USD volume directly from the user's balance, and embeds the current fee rate in the EIP-712 signature to prevent replay attacks when parameters are updated. All operations execute atomically within the V4 unlockCallback, providing maximal security and MEV resistance while eliminating the risk of relayer loss.
TL;DR: A battle-tested periphery contract for Uniswap V4 that makes gasless swaps relayer-profitable by mandating stablecoin involvement and atomic fee burning, while enabling swap-only mining rewards.
Motivation
Gasless trading is required for mass adoption, yet all existing solutions expose relayers to sustained losses from spam and zero-fee transactions.
This ERC eliminates relayer risk while preserving atomic execution and requiring no trusted forwarder.
Specification
The periphery contract MUST implement:
uint256 public gaslessFeeRate; // denominator, 100 = 1%
mapping(address => bool) public isStableCoin;EIP-712 ensures structured signing with replay protection via the embedded feeRate.
Swap(address caller,PoolKey key,SwapParams params,bytes hookData,uint256 feeRate,uint256 deadline)The feeRate field must equal the contract's current gaslessFeeRate at the time of signing.
Rationale
This is the only known gasless swap design that is inherently profitable for relayers, maintains atomic execution, and requires no trusted forwarder.
Backwards Compatibility
Fully compatible with Uniswap V4 core and Permit2.
Security Considerations
- Replay protection via embedded feeRate
- Atomic execution in callback
- Relayer zero-loss guarantee via callStatic simulation
- No trusted forwarder
- Battle-tested at scale
Copyright
Copyright and related rights waived via CC0.
