Index / VolatilityFee

pattern · MIT · last updated 2026-08-27

VolatilityFee

LP fee rises with |currentTick − lastTick| since the previous swap.

First-party teaching hook inspired by Clanker-style tick-accumulator dynamic fees. Stores lastTick per pool; beforeSwap reads current tick from StateLibrary and adds tickFactor × |Δtick| to baseFee, capped at maxFee. afterSwap updates lastTick. Contrast surge-fee.yml (size vs liquidity) and volatility-oracle.yml (time ramp). Requires dynamic fee pool. Experimental. Forge tests in test/VolatilityFee.t.sol. Listing is not an audit.

Permission bits

These bits must match the deployed address. Confirm on-chain before you route.

afterInitializebeforeSwapafterSwap

Solidity

Excerpt from contracts/VolatilityFee.sol. Copy the full file to implement this. Not an audit.

// SPDX-License-Identifier: MIT
function feeFor(PoolKey calldata key) public view returns (uint24) {
    (, int24 tick,,) = poolManager.getSlot0(key.toId());
    uint256 move = _absTickDelta(tick, lastTick[key.toId()]);
    uint256 total = uint256(baseFee) + move * uint256(tickFactor);
    if (total > maxFee) return maxFee;
    return uint24(total);
}

Spec

FAQ

Can I paste this into production? The snippet is an excerpt. Use the full file at the source URL, match flags to the address, and treat this page as a map, not a guarantee.

How do I build this safely? Start with secure v4 hooks and the OpenZeppelin hooks guide.