Uniswap v3 vs v4: what changed and why hooks matter

7 November 2026

Uniswap v4 launched in January 2025. Trading feels the same from the outside, but under the hood it changed a lot. Here are the differences that matter.

1. Hooks

The big one. In v3 every pool behaved the same way. In v4 a pool can have a hook: a small contract that runs on swaps and liquidity changes. That's what makes taxes, launch protection, liquidity locks and custom fees possible inside Uniswap itself.

2. One contract for every pool

In v3 each pool was its own contract. In v4 all pools live inside one contract called the PoolManager. Creating a pool is much cheaper, and trades that hop through several pools cost less gas.

3. Native ETH

v3 needed WETH, the wrapped version of ETH. v4 pools can hold plain ETH directly, which saves a step and some gas.

4. Cheaper multi-step trades

v4 only settles what you owe or are owed at the end of a transaction, instead of moving tokens after every step. Routes through several pools get cheaper.

5. Fees can be anything

v3 had a few fixed fee tiers. In v4 a pool can use almost any fee, and with a hook the fee can even change from trade to trade. See dynamic fees explained.

What stays the same

Concentrated liquidity works like in v3: liquidity providers choose the price range their money works in. And as before, nobody controls a pool once it exists; with a hook, its rules are fixed too.