Wei is the smallest unit of Ether, which is the native currency of the Ethereum network. Just like cents are to dollars, wei represents a fractional part of Ether, making it possible to handle very small transactions.One Ether is equal to 1 quintillion wei (1 ETH = 1,000,000,000,000,000,000 wei). This vast number allows for precision in transactions, especially given Ethereum’s capabilities in executing smart contracts and decentralized applications. Using wei helps to avoid issues related to rounding errors that can occur with larger units. For instance, in complex applications or microtransactions, dealing in wei ensures that every tiny fraction of value can be accounted for accurately.In summary, wei is essential for enabling detailed and precise financial operations within the Ethereum ecosystem, catering to a wide range of use cases from simple transfers to intricate smart contract interactions.