Hy4 preview represents a cutting-edge open source Mixture-of-Experts flagship model tailored for a variety of real-world productivity tasks, including software engineering, office activities, game development, and scientific exploration. This model boasts a staggering total of 770 billion parameters, with 49 billion activated per token, and features an impressive 1 million-token context window, allowing it to efficiently manage large codebases, vast document collections, and complex multi-step processes. The architecture consists of 78 layers that integrate Gated DeepSeek Sparse Attention alongside IndexCache for reusing sparse indices across layers, while also employing identity Hyper-Connections to enhance the flow of information between layers. Additionally, a dedicated Multi-Token Prediction layer facilitates speculative decoding, further enhancing its capabilities. Hy4 preview is crafted to comprehend, plan, debug, and validate intricate engineering projects, while also achieving notable improvements in the quality of front-end visuals and interaction design, thereby making it an invaluable asset for professionals across various domains.