Uniswap v4 is increasingly becoming a venue for pools that can change how trading works without forcing users to migrate liquidity or switch token contracts. Over the past 30 days, Uniswap v4 processed $39.7 billion in trading volume—roughly half of Uniswap’s total volume—and generated 64% of the protocol’s fee revenue, according to Uniswap’s public interface data.
The growth is tied to “Hooks,” optional smart contracts attached to individual v4 pools. Hooks can add custom instructions before or after a swap, alter trading fees, restrict access, distribute rewards, or deploy idle assets into other protocols. Their rising use gives projects more flexibility than earlier decentralized exchange designs, but it also makes the code and upgrade controls behind each pool more relevant to traders and liquidity providers.
One early October example came from Claus, an Ethereum memecoin project that changed its pool’s fee logic while retaining the same token address and pool setup. On Oct. 8, the Hook registry associated with Claus showed its fee contract changing from FeeWeatherHook to FeePrivacyHook. The switch followed an Oct. 6 update that removed an arbitrage-related feature while preserving other functions.
Claus had previously directed trading fees toward token buybacks, burns, liquidity additions and rewards for NFT holders. Its earlier Hook design also used weather information from London Heathrow to decide how fees were allocated: rainy conditions favored burns, sunny weather favored liquidity, and unavailable weather data triggered an equal split.
That kind of feature would have been difficult to add at the exchange layer in earlier versions of automated market makers. Uniswap v4 instead uses a shared PoolManager contract to handle swaps and accounting, while pools maintain their own liquidity parameters and can attach a Hook for additional logic. A Hook may run at defined stages of a transaction, including beforeSwap and afterSwap, as well as during liquidity additions and withdrawals.
Proxy design allows pool logic to change
A pool’s Hook address forms part of its identity when the pool is created. Replacing a Hook with an entirely new contract address would therefore generally require a new pool, along with a liquidity migration.
Claus avoided that process by using a proxy structure. The pool calls a Hook at a fixed address, while the proxy can redirect execution to an updated implementation contract. The approach allows the pool to preserve its address, accumulated liquidity and user-facing setup while changing the rules behind it.
That convenience comes with a governance trade-off. A proxy can reduce the disruption of moving to a new pool, but it also means users need to understand who controls upgrades and which functions can be changed. Fee levels, reward destinations, access checks and trading behavior may all be affected by the scope of the upgrade authority.
Projects have long experimented with custom economic rules through token contracts. So-called tax tokens, for example, can deduct a percentage from each transfer. Such designs have often created compatibility problems because decentralized exchange routers may expect a full token amount to arrive during a swap while the token contract sends less after applying its fee.
Hooks move those rules to the pool rather than the token. A pool-level charge can apply to swaps without affecting ordinary wallet-to-wallet transfers, reducing one source of incompatibility. The same model can support variable fees during volatile markets, restricted pools for approved participants, and mechanisms that share proceeds from trading activity.
Arbitrage capture is a major Hook use case
One of the more commercially relevant Hook designs targets arbitrage. Price differences between pools are commonly captured by bots that buy an asset in one venue and sell it in another. A Hook can detect such a gap, execute a rebalancing trade within the same transaction and direct the resulting profit according to rules set by the pool.
Depending on the implementation, the proceeds could go to liquidity providers, traders, a project treasury or other designated recipients. This changes the usual allocation of arbitrage returns, although the outcome depends on the specific contract’s execution logic, gas costs and ability to compete with external searchers.
Uniswap released additional Hook-based pool designs in October. VolatilePair, initially deployed for an ETH/USDC pool on Ethereum, applies separate fees to buys and sells. StablePair, a design aimed at stable assets, reached $3.1 billion in trading volume during its first four weeks, according to an announcement connected to its release.
Other applications extend beyond fees. DualPool is designed to lend idle market-making assets and recall them when swaps require inventory. Spark moved $150 million of liquidity to Uniswap v4 and has planned an integration with DualPool. Auction-style Hooks can also distribute tokens over time before creating a liquidity pool at a clearing price. Aztec used an auction Hook in a sale that raised about $59 million from more than 17,000 bidders.
Tokenized stocks add a reason for adaptive fees
On Robinhood Chain, the decentralized exchange project Fables has used Hooks to modify fees based on factors including time and volatility for tokenized stock trading. The design addresses a practical market-structure issue: tokenized shares can continue trading onchain even while the underlying stock market is closed.
Bitquery reported in early September that roughly one-third of Uniswap v4 pools on Robinhood Chain used Hooks, but those pools represented 74.5% of trading activity. The gap suggests that custom pool behavior has been concentrated in the network’s more active venues rather than spread evenly across all deployments.
Controlled-access pools have also emerged as a use case. In July, Uniswap Labs introduced permissioned pool designs that use Hooks to check whether a wallet can trade or provide liquidity. Uniswap Labs named Superstate, Securitize and Dowgo as early partners for that framework, which could be used for tokenized assets where participation rules are required.
Tooling providers are now packaging Hook functions into deployable templates. Programmable.market has offered “Classic” configurations for custom buy and sell fees paired with permanently locked ETH pools, as well as an API option for tailored setups. Its Robinhood Chain documentation describes a default 0.2% fee sent to a specified address and states that its contracts have not undergone an external audit or public security competition.
Hookrfun, another Robinhood Chain tool suite, lists 22 Hook components, including anti-sniping and auto-burn functions. Its “What The Hook” component outlines a default allocation for arbitrage proceeds in third-party pools: 45% to liquidity providers, 5% to traders, 40% to a treasury and 10% to referrers.
Solana applies rules at the token level
Solana has taken a structurally different approach. Uniswap is not deployed on the network, where liquidity is spread across venues such as Raydium, Orca and Meteora rather than coordinated by a shared PoolManager contract.
Under Solana’s Token-2022 standard, token creators can embed transfer Hooks directly into a token. Those rules execute on every transfer, including swaps and wallet-to-wallet movements, and can reject transactions that do not meet eligibility conditions.
The Solana launch platform Hooked issues tokens with transfer Hooks by default and offers 39 preset rule templates. One template imposes a 15-minute holding period before a buyer can sell. Hooked charges a 1% fee on each trade and says most of that fee is used to buy back and burn its native token.
Exchange support can limit how such tokens trade. Raydium requires administrative approval for pools involving tokens with transfer Hooks. Meteora can support them on bonding curves, but the Hook logic is removed if an asset later graduates to a main pool. Hooked has therefore kept some tokens on bonding curves to preserve enforcement of its rules.
The distinction affects user choice. In Uniswap v4, rules are tied to a specific pool, allowing the same token to trade in both standard and Hook-enabled venues. On Solana, a transfer Hook attaches conditions to the token itself, so the same logic follows it across transfers and trading venues.
To explore Hook-powered trading tools beyond Uniswap, check out Toobit’s DEX trading guide for deeper insights.
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