Uniswap v4 A game-changing evolution from v3

Uniswap, the popular decentralized exchange protocol, has unveiled its latest version, v4, with significant improvements over its predecessor, v3. The standout feature is the adoption of the “Singleton” design pattern, revolutionizing the automated market maker (AMM) model and optimizing gas usage.

1/ Uniswap v4 makes some big changes to v3.

Like rearchitecting Uniswap’s AMM to have only one contract 🙀

It’s called the “Singleton” design pattern and it’s a big gas saver.🧵

— Uniswap Labs 🦄 (@Uniswap) June 20, 2023

In the previous version, v3, each pool was represented by a separate smart contract, leading to increased gas costs when transferring tokens between different pools. However, with the introduction of the Singleton design pattern in v4, all pools are consolidated within a single contract. This consolidation not only simplifies the architecture but also significantly reduces gas expenses for users.

One of the key benefits of the Singleton design is that it eliminates the need to transfer tokens between pools in different contracts, especially for multi-hop routes. This optimization minimizes gas fees and provides a more seamless swapping experience for Uniswap users. Early estimates suggest that creating a new pool in v4 is approximately 99% cheaper than in v3, thanks to this consolidation.

Additionally, the Singleton architecture enables the capture of balance snapshots within the same contract, enhancing efficiency and reducing gas costs even further. By performing all necessary calculations within a single contract, a technique known as “Flash accounting,” Uniswap can save gas by transferring tokens based on net balances rather than individual transactions.

Furthermore, the Singleton design pattern and flash accounting have paved the way for the elimination of fee tiers. In v3, fee tiers were limited to prevent liquidity fragmentation. However, with the advancements in v4, it is now considerably more cost-effective to navigate between different pools. Users can now freely set any swap fee or dynamically adjust fees, offering greater flexibility and customization options.

It is worth noting that the Singleton design pattern is just one of the notable features in Uniswap v4. For more information on other features such as “hooks,” we encourage readers to explore our separate thread dedicated to diving deeper into these aspects.

With the introduction of the Singleton design pattern and flash accounting, Uniswap v4 marks a significant milestone in the evolution of the decentralized exchange landscape. The improvements in gas efficiency, reduced costs, and enhanced flexibility empower users to engage more seamlessly in decentralized trading and liquidity provision.