Qtum is an open source Blockchain project, developed by the Singapore-based Qtum Foundation. Qtum is a hybrid blockchain application platform with a core technology that consists of fork of bitcoin core, an Account Abstraction Layer and Proof-of-Stake consensus, aiming at tackling industry use cases; this makes Qtum the champion toolkit for building trusted decentralized applications, fitted for real-world, business oriented use cases. The Qtum Foundation plans to be the public blockchain for business and various industries, including Mobile Telecommunications, Counterfeit Protection, Finance, Industrial Logistics, and Manufacturing. The Qtum project merges the trustworthiness of Bitcoin’s inexhaustible blockchain with the infinite possibilities of smart contracts, into a business-friendly blockchain, built upon the Bitcoin’s UTXO transaction model. With UTXO it is simpler to validate a transaction, by verifying that the transaction has been confirmed by the blockchain, making it more scalable, while transactions can be easily processed in parallel. Qtum’s hybrid nature, in combination with a first-of-its-kind PoS consensus protocol, allows Qtum applications to be compatible with major blockchain ecosystems, while providing native support for mobile devices and IoT appliances.