RatchetFloor

A price floor that only ever moves up.

A production Uniswap v4 hook. It holds no funds and takes no fee for itself. No owner, no pause switch, no upgrade path.

• Site: https://ratchet-floor.pages.dev
• Catalogue: https://hookforge.pages.dev
• Contract: src/hooks/RatchetFloorHook.sol
• Licence: Apache-2.0

How it works

A token's floor price is normally a promise: a treasury that says it will bid, a team that says it will buy back. Promises are only as good as the balance behind them and the people holding the keys. This hook makes the floor a property of the pool instead.

It records the highest tick the pool has ever reached and refuses to let the price settle more than offsetTicks below it: floor = max(floor, highWaterTick - offsetTicks) The floor is monotone by construction. It has no setter, no owner and no emergency path, so it cannot be lowered by anyone, including whoever deployed the pool. A rally raises it permanently; a decline never moves it.

How a swap meets the floor matters, so it is worth being precise. Uniswap v4 swaps already take a sqrtPriceLimitX96, and {sqrtPriceFloorX96} returns exactly the value to pass: a swap carrying it fills as much as the floor allows and stops there, which is the behaviour a seller wants. The afterSwap check is the backstop for callers that pass no limit, and for those the swap reverts rather than partially filling.

Routers should read the floor; the revert exists so that a router which does not cannot break the invariant. One tick is one basis point to within rounding, so offsetTicks = 2000 is a floor twenty percent below the high.

Prior art

Floor prices are usually a treasury commitment (protocol-owned liquidity, OHM-style backing) or a buyback hook that spends fees defending a level. Both depend on a balance and on whoever can move it. Enforcing a monotone floor as an invariant of the pool, with no treasury and no key, is a different construction: nothing is spent defending it and nothing can lower it.

Where it does not help

This guarantees the pool will not print below the floor. It does not guarantee anyone can sell at the floor, because it holds no capital: once the price reaches the floor there is simply no more selling into the pool, and a holder who wants out has to wait for the price to recover or trade elsewhere. It converts a liquidity risk into a liquidity halt, honestly and predictably, but it does not make the risk disappear. A pool that needs a real bid at the floor needs a treasury behind it, and this is not that.

Using it

Uniswap v4 removed hookData from initialize, so per-pool parameters arrive out of band. Fix them for a pool key whose pool does not exist yet, then initialize. Nobody can change them afterwards, including you.

hook.configure(
    key,
    RatchetFloorHook.Config({
        offsetTicks: /* uint24 */ 0
    })
);

poolManager.initialize(key, startingSqrtPriceX96);

Parameters

Parameter	Type	Units
offsetTicks	uint24	ticks

What it reverts with

Error	Meaning
BelowFloor(int24,int24)	The swap would leave the pool below its floor. Pass sqrtPriceFloorX96 as the swap's price limit.
InvalidOffset()	offsetTicks was zero, which would pin the floor to the current price and stop the pool trading down.
PoolAlreadyInitialized()	The pool already exists, so its configuration is final.
PoolNotConfigured()	The pool was initialized without a configuration for this hook.

The callbacks it claims

Uniswap v4 reads a hook's permissions from the low fourteen bits of its own address, which is why deploying one means mining a CREATE2 salt. This hook claims 2 of the fourteen:

• afterInitialize
• afterSwap

Mask: 0x1040, so every deployment of this hook has an address ending in those bits.

It says what it is, on-chain

Every hook in this family implements IHookMetadata: four view functions that let an indexer, a wallet, a router or an agent identify a hook from its address alone, with no registry in the loop.

cast call $HOOK "hookName()(string)"    # RatchetFloor
cast call $HOOK "hookVersion()(string)" # 1.0.0
cast call $HOOK "specURI()(string)"     # the machine-readable manifest
cast call $HOOK "hookTags()(string[])"  # price-floor, launch, no-admin, oracle-free

The manifest this repository ships as hook.json is what specURI() points at.

Build and test

git clone --recurse-submodules https://github.com/nirholas/ratchet-floor
cd ratchet-floor
forge build
forge test

Foundry 1.7 or newer, Solidity 0.8.26, EVM version cancun (Uniswap v4 requires transient storage).

Deploy

# Dry run: mines the salt and prints the address without sending anything.
forge script script/Deploy.s.sol --rpc-url $RPC_URL

# For real.
forge script script/Deploy.s.sol --rpc-url $RPC_URL --broadcast --verify

Needs PRIVATE_KEY in the environment and a funded deployer on the target chain. See docs/deploying.md.

Status

Unaudited. Built to an audited shape, on OpenZeppelin's audited hook bases, and tested against a real PoolManager. No third party has reviewed it. Read "where it does not help" above before putting money behind it.

Not affiliated with Uniswap Labs.