---
eip: 8090
title: Relayer-Protected Gasless Swaps
description: Gasless swap pattern guaranteeing relayer profitability via mandatory stablecoin involvement and automatic fee burning
author: YC Wong (@wyc-dev)
discussions-to: https://ethereum-magicians.org/t/erc-8090-gasless-minting-swap-standards-in-uniswap-v4/26711
status: Draft
type: Standards Track
category: ERC
created: 2025-11-23
requires: 712
---

## Abstract

[EIP-8090](./eip-8090.md) 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](./eip-712.md) 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:

```solidity
uint256 public gaslessFeeRate; // denominator, 100 = 1%
mapping(address => bool) public isStableCoin;
```

[EIP-712](./eip-712.md) 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

<!-- TODO: flesh this out more -->

## Copyright

Copyright and related rights waived via CC0.