Tencent Open-Sources Hunyuan Hy4 with 770B Parameters and 1-Million-Token Context

Tencent has released the preview version of its Hunyuan Hy4 large language model, built on a mixture-of-experts (MoE) architecture with 770B total parameters, 49B activated at a time, and a 1-million-token context window. The new generation is more than twice the size of Hy3 — which had 295B total parameters, 21B active parameters and 256K context — and its long-context capacity has grown roughly four-fold. Rather than lean only on general benchmarks, Tencent is steering Hy4 toward concrete tasks in coding, office work, gaming and scientific research. The model can build a Three.js 3D website from scratch, craft a playable game demo in Unity, or work through 72 financial documents at once to catch duplicate reimbursements, over-limit expenses and budget anomalies. Hy4 was trained and iterated along with Tencent products including WorkBuddy and CodeBuddy, and it has begun contributing to its own development — helping optimize training methods, data strategy, evaluation systems and underlying operators before running experiments and adjusting its approach based on the results. The preview is already integrated into WorkBuddy, CodeBuddy, Yuanbao, ima, Tencent Cloud TokenHub and OpenRouter, with Tencent having flagged earlier in its earnings report that Hy4 would surpass Hy3 and that real product feedback would be a key source for training.