Paradex, a crypto-derivatives exchange launched on Starknet's first Appchain, offers perpetual futures trading with deep liquidity, capital efficiency, and performance while ensuring transparency and self-custody. The collaboration between Paradex and StarkWare demonstrates the power of Starknet for high scale and low-cost applications that require custom specifications while maintaining decentralization and self-custody. Starknet Appchains allow for scaling and customization without relying on others' protocols, benefiting from Ethereum-grade security and decentralization. Paradex leveraged STARK technology and Cairo to build a customized Appchain for their derivative exchange needs.