What Is Uniswap v4?
Uniswap v4 is the latest iteration of the world's largest decentralized exchange by volume. Launched in early 2026, it introduces a singleton contract architecture, hooks, and flash accounting — three upgrades that fundamentally change how AMM liquidity works on Ethereum and its L2s.
Uniswap consistently processes over $40 billion in monthly volume across all versions. Version 4 aims to consolidate that liquidity under a single, more gas-efficient contract while opening the door to programmable pool behavior.
Key Features: Hooks, Singleton & Flash Accounting
Hooks — Programmable Pool Logic
Hooks are external smart contracts that attach to individual pools and execute code at predefined points: beforeSwap, afterSwap, beforeAddLiquidity, afterAddLiquidity, beforeRemoveLiquidity, afterRemoveLiquidity, and beforeDonate/afterDonate.
This makes pools infinitely customizable. Developers have already deployed hooks for:
- Dynamic fee hooks — adjust swap fees based on volatility or oracle data
- On-chain limit orders — place limit orders that execute within the AMM
- TWAMM — time-weighted average market maker for large orders
- Auto-compounding — reinvest fee earnings into LP positions
- KYC/whitelist hooks — restrict pool access to verified addresses
Singleton Contract
Unlike v3 where each pool was its own contract, v4 stores all pools in a single contract. This eliminates expensive factory deployments and allows internal token transfers between pools without touching ERC-20 contracts — cutting multi-hop gas by up to 40%.
Flash Accounting
Token balances are tracked internally during a transaction and only settled at the end. If you swap ETH → USDC → WBTC, the intermediate USDC transfer never hits the ERC-20 contract. Only the net ETH debit and WBTC credit are settled on-chain.
How to Swap on Uniswap v4 — Step by Step
- Connect wallet — Go to app.uniswap.org and connect MetaMask, Rabby, or any WalletConnect wallet.
- Select network — Choose Ethereum, Arbitrum, Base, Optimism, or Polygon from the chain selector.
- Choose tokens — Select input token (e.g., ETH) and output token (e.g., USDC). The router automatically finds the best v4 or v3 route.
- Review route — Check the price impact, minimum received, and gas estimate. Multi-hop swaps through the singleton contract will show lower gas.
- Approve & swap — Approve the token (one-time for ERC-20s), then confirm the swap transaction.
- Verify — Check the transaction on Etherscan or your wallet's activity tab.
Providing Liquidity on Uniswap v4
Liquidity provision in v4 works similarly to v3's concentrated liquidity model — you choose a price range and deposit two tokens. The key difference is that v4 pools can have hooks that modify LP behavior:
- Auto-rebalancing hooks keep your position centered around the market price
- Fee-tier hooks dynamically adjust fee rates to maximize LP returns
- Reward hooks distribute additional token incentives to LPs
Before depositing, always check which hook is attached to the pool. Hooks are immutable per pool — you can verify the hook contract on the pool's details page.
Uniswap v4 Fees
| Fee Type | Uniswap v4 | Notes |
|---|---|---|
| Swap fee | Dynamic (hook-set) or 0.01%–1% | Hooks can adjust fees per-swap |
| Pool creation | Near zero | No new contract deployment needed |
| LP withdrawal | No protocol fee | Only gas costs |
| Gas (ETH swap) | ~$0.80–$2.50 mainnet | 40% cheaper multi-hop vs v3 |
| Gas (L2 swap) | ~$0.01–$0.10 | Arbitrum/Base/Optimism |
| Protocol fee | Up to 0.1% (governance) | UNI governance can activate |
Uniswap v4 vs Alternatives
| Feature | Uniswap v4 | Uniswap v3 | Curve v2 | Balancer v3 |
|---|---|---|---|---|
| Architecture | Singleton | Factory | Factory | Vault |
| Programmable pools | Hooks | No | No | Custom pools |
| Concentrated liquidity | Yes | Yes | Partial | Yes |
| Multi-hop gas | ~40% cheaper | Baseline | Similar | Internal balances |
| Monthly volume | $40B+ | $40B+ (combined) | $5B+ | $2B+ |
| Chains | ETH + 4 L2s | ETH + 8 chains | ETH + 5 chains | ETH + 3 chains |
UNI Token Overview
UNI is the governance token of the Uniswap protocol. Holders vote on protocol fees, treasury allocations, and governance proposals.
- Total supply: 1 billion UNI
- Circulating supply: ~753 million (March 2026)
- Key utility: Governance voting, potential fee-switch activation
- Fee switch: UNI governance approved a protocol fee of up to 0.1% on select pools — revenue accrues to the DAO treasury
Risks of Using Uniswap v4
Pros
- Hooks enable unlimited customization — limit orders, dynamic fees, TWAMM
- Singleton contract cuts gas costs significantly on multi-hop swaps
- Deepest on-chain liquidity for major pairs
- Open-source and battle-tested codebase
- Deployed on 5 chains including low-cost L2s
Cons
- Malicious hooks can drain funds — always verify hook contracts
- Concentrated liquidity requires active management or hook assistance
- Impermanent loss remains a risk for volatile pairs
- New architecture means less auditing history than v3
- MEV (sandwich attacks) still affects on-chain swaps
Frequently Asked Questions
What are Uniswap v4 hooks?
Hooks are smart-contract plugins that execute custom logic at specific points during a pool's lifecycle — before/after swaps, liquidity changes, and donations. They enable features like dynamic fees, on-chain limit orders, TWAMM, and auto-compounding without changing the core protocol.
Is Uniswap v4 cheaper than v3?
Yes. The singleton architecture stores all pools in one contract, cutting pool creation gas by ~99%. Flash accounting nets token transfers internally, reducing multi-hop swap gas by up to 40% compared to Uniswap v3.
Can I migrate my Uniswap v3 position to v4?
There is no automatic migration. You must withdraw liquidity from v3, then re-deposit into a v4 pool. Several front-end aggregators offer one-click migration tools that handle both steps in a single transaction.
What chains support Uniswap v4?
Uniswap v4 is deployed on Ethereum mainnet, Arbitrum, Optimism, Polygon, and Base as of March 2026, with more L2 deployments planned. Each chain uses the same singleton architecture.