Serum is a protocol and ecosystem that brings unprecedented speed and low transaction costs to decentralized finance. It is built on Solana and is completely permissionless. Ecosystem partners can compose with Serum’s on-chain central limit order book to share liquidity and power markets-based features for institutional and retail users. More specifically, Serum's on-chain central limit order book and matching engine provides liquidity and price-time-priority matching to traders and composing projects. Users benefit from this exchange model through the ability to choose the price, size and direction of their trades. Composing projects benefit from Serum’s existing architecture, bootstrapped liquidity, and matching service.