Sei is presented as a new layer 1 blockchain specifically engineered for trading applications. It aims to overcome the limitations of existing blockchains by introducing protocol-level improvements focused on speed and efficiency. Key innovations include a "Twin-Turbo" consensus mechanism for faster block propagation and optimistic block processing, along with parallelization techniques for transaction handling. Furthermore, Sei incorporates a native order matching engine that decentralized exchanges can utilize, featuring frequent batch auctioning to mitigate front-running. The design prioritizes customizable trading experiences and efficient order execution with minimal fees at the base layer.