Alephium is a high-throughput public blockchain platform that could scale to ten thousands of transactions per second without sacrificing decentralization and security. The platform is built on its innovative sharding algorithm called BlockFlow. BlockFlow exploits a scalable UTXO model, combining DAG and sharding, to be the first sharding algorithm supporting cross-shard transactions natively. Alephium also designs a practical and scalable solution for decentralized applications.