Uniswap V4 vs V3: Architectural Changes and Technical Innovations with Code Examples

Discover Uniswap V4 architectural updates and technical innovations: new hook system, singleton pattern, flash accounting, fee tier flexibility, native token support.

Uniswap V4 introduces a series of updates that build upon the Uniswap V3 concentrated liquidity model, focusing on improved efficiency and flexibility. The purpose of this article is to highlight the key architectural changes and technical innovations in Uniswap V4, including the new hook system, singleton pattern, flash accounting, fee tier flexibility, and native token support. These updates address various limitations of V3, such as gas inefficiencies and limited customizability in the AMM design. Code snippets/links have been included to contrast with V3 where appropriate.

Singleton pattern & ERC-6909

One of the most significant changes in Uniswap V4 is the move to a singleton architecture where all assets are stored in and managed by a single PoolManager contract. This represents a fundamental shift from the V3 factory pattern where each pool required its own contract deployment and underscores the importance of a secure core protocol, as the singleton can be considered a honeypot for attackers.

The singleton approach dramatically reduces gas costs and improves capital efficiency by consolidating all token pairs into a single contract. This consolidation eliminates the need for routing token swaps between each individual pool, resulting in significant gas savings and improved system efficiency.

V4 introduces several other optimizations for state management in PoolManager, such as the base Extsload functionality that significantly reduces contract bytecode size by loading arbitrary storage slots; however, this does not come at the expense of developer experience as StateLibrary exposes familiar function names to wrap the abstract calculation of storage slots.

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Link: https://www.cyfrin.io/blog/uniswap-v4-vs-v3-architectural-changes-and-technical-innovations-with-code-examples?utm_source=substack&utm_medium=email