UniswapV4Hook
EthereumRegisteredHook that charges a 1.7% fee on each swap: buy-side fees accumulate in an ETH pot for periodic buyback-and-burn (triggered every 20 swaps), while sell-side token fees are immediately queued for burning. Liquidity addition is permanently restricted to one deposit, and exact-output swaps always revert. When the token's `timeBased` flag is set, sell-side swaps are additionally restricted to an owner-approved allowlist (the `hasValue` mapping), reverting for any seller not on the list.
What it can do
Its code executes inside each trade in pools that use it.
It can take or add tokens during a swap. Fees, burns and custom curves work this way, and so do scams.
It checks every deposit before it goes in.
It runs when a pool is created, often to lock in that pool’s settings.