Order books have proven highly effective in traditional finance (TradFi) but reveal limitations when applied to decentralized finance (DeFi). Many protocols still rely on off-chain order books as matching engines and handle settlement on-chain. Others have eliminated centralization and replaced order books with Automated Market Makers (AMMs).

Perpetual future contracts, also known as perpetual swaps or just perpetuals, are a type of derivative instrument that allows traders to speculate on the price movements of an underlying asset without owning the asset itself. Perpetual future contracts differ from traditional futures contracts in that they do not have an expiration date. Instead, they are designed to maintain a perpetual duration, allowing traders to hold positions for as long as they desire. This feature eliminates the need for traders to roll over their contracts or worry about settlement dates, making perpetual contracts more convenient and accessible.