Index / Doppler

product · BUSL-1.1 · last updated 2026-08-27

Doppler

Whetstone bonding-curve hook: rebalance slugs before swap, migrate when proceeds cap hit.

Doppler is Whetstone Research production code (BUSL-1.1). The hook runs a time-epoch bonding curve: beforeSwap rebalances concentrated liquidity slugs when a new epoch starts, tracks totalTokensSold and totalProceeds, and blocks swaps before startTime or after migration. beforeAddLiquidity reverts (CannotAddLiquidity); LPs are the hook's slug positions, not external adds. Study for launchpad / LBP-style v4 hooks. Do not deploy without a Whetstone license. Excerpt shows permissions and epoch gate in beforeSwap. Full file at the permalink. Not an audit.

Permission bits

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

beforeInitializeafterInitializebeforeAddLiquiditybeforeSwapafterSwapbeforeDonate

Solidity

Excerpt from src/initializers/Doppler.sol. Production hook. Study the callbacks, do not paste it as your factory. Not an audit.

// SPDX-License-Identifier: BUSL-1.1
function getHookPermissions() public pure override returns (Hooks.Permissions memory) {
    return Hooks.Permissions({
        beforeInitialize: true,
        afterInitialize: true,
        beforeAddLiquidity: true,
        beforeRemoveLiquidity: false,
        afterAddLiquidity: false,
        afterRemoveLiquidity: false,
        beforeSwap: true,
        afterSwap: true,
        beforeDonate: true,
        afterDonate: false,
        beforeSwapReturnDelta: false,
        afterSwapReturnDelta: false,
        afterAddLiquidityReturnDelta: false,
        afterRemoveLiquidityReturnDelta: false
    });
}

function _beforeSwap(...) internal override returns (bytes4, BeforeSwapDelta, uint24) {
    if (block.timestamp < startingTime) revert CannotSwapBeforeStartTime();
    // rebalance slug liquidity when epoch advances, then pool executes swap
}

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.