Tencent announced the release of Hy4 preview, an open-source large language model with 770 billion total parameters and 49 billion active parameters and a context window of more than one million tokens. The model is intended for real‑world productivity tasks such as coding, office work and scientific research. It is available through WorkBuddy, CodeBuddy, Yuanbao, ima and other Tencent products, and can also be accessed via Tencent Cloud TokenHub and OpenRouter.
The preview is free for two weeks on WorkBuddy and CodeBuddy, and free access to Hy3 on those platforms has been extended until September 30. In an internal blind evaluation, Hy4 preview scored an average of 2.99 out of four, slightly higher than GLM‑5.3 (2.92) and Kimi K3 (2.94). The model was trained on data co‑created with Tencent experts and refined through deep integration with productivity tools.
In software engineering, Hy4 preview shows improved understanding, planning, debugging and validation for long‑context development, as well as better visual quality for front‑end work. In office settings it enhances comprehension of complex environments and financial analysis, and supports data analysis and cross‑document collaboration for documents, spreadsheets and presentations. In game development it can generate a playable prototype from a single natural‑language prompt and interact with game engines. In scientific research it improves reasoning and problem solving in AI, molecular dynamics, condensed‑matter physics and mathematics.
During its development, Hy4 preview participated in its own training optimization, helping adjust training methods, data strategies, evaluation frameworks and low‑level operators. The model also identified and optimized bottlenecks in its inference system, raising end‑to‑end throughput by 31.8 % compared with baseline performance across varying context lengths and concurrency levels.
API pricing is set at $0.834 per million input tokens, $2.501 per million output tokens and $0.042 per million cache‑hit tokens. Tencent plans to release the next generation of Hy4 models soon.

