Hy4 Preview
Tencent Hunyuan's open-weight flagship, co-designed with its own dev tools
Tencent open-sourced Hy4 Preview on August 28, 2026, a 770-billion-parameter mixture-of-experts model with 49 billion active parameters and a 1 million token context window, released under Apache 2.0. Rather than building a general chat model, Tencent’s Hunyuan team trained it on work data from software engineers, game developers, finance analysts, and security experts, and co-designed it alongside the company’s own CodeBuddy and WorkBuddy products.
In Tencent’s internal blind evaluation, where 163 experts judged 203 real engineering tasks, Hy4 Preview averaged 2.99 out of 4.00, edging out GLM-5.3 at 2.92 and Kimi K3 at 2.94. API pricing runs $0.834 per million input tokens and $2.501 per million output tokens, with cached input at $0.042 per million.