Project Serum was a decentralized protocol and ecosystem designed to bring unprecedented speed and low transaction costs to decentralized finance (DeFi). Built on the Solana blockchain, its core innovation was a fully on-chain central limit order book (CLOB), which allowed it to match the performance of centralized exchanges. The project was heavily supported and developed by a consortium including FTX and Alameda Research. Following the collapse of FTX in November 2022, control over the protocol's upgrade keys was compromised, rendering it unsafe. Consequently, the original Serum protocol was shut down, and the community forked the code to create OpenBook, a community-led successor.