Cardstack is a decentralized platform that aims to make blockchain usable and scalable for the mass market. At this platform, users can be provided with a feature named Cardstack Framework, a comprehensive SDK to create card-based blockchain apps. 

CARD is an Ethereum based token developed by Cardstack to be a medium of exchange within the platform. It will be used to reward open-source developers, also, CARD holders can become miners to validate transactions and earn fees.