Ekiden is a decentralized, orderbook-based hybrid exchange built on the Aptos blockchain. It combines an off-chain Central Limit Orderbook (CLOB) with deferred on-chain settlement to deliver high performance, transparency, and capital efficiency for both spot and perpetual futures markets. Built on a rollup-like architecture with Merkle-based proofs, Ekiden is designed to meet the demands of high-frequency traders and institutional DeFi participants.