On August 28, 2026, Tencent Hunyuan released and open-sourced Hy4 preview — a mixture-of-experts model with 770B total parameters, 49B active, and a context window over 1 million tokens, aimed at software engineering, office work, and scientific research.
2026-08-29 · by Moe Ameen
On August 28, 2026, Tencent's Hunyuan team released and open-sourced Hy4 preview, a next-generation large language model. It is a mixture-of-experts (MoE) design with 770 billion total parameters and roughly 49 billion active per step, paired with a context window Tencent describes as exceeding 1 million tokens. The stated target is productivity work — software engineering (debugging and long-context code tasks), office and financial analysis, game development, and scientific research including AI R&D and physics simulation — rather than chat or creative content.
Tencent published the model weights openly on Hugging Face, ModelScope, GitCode, and CNB, and also shipped a lower-precision Hy4 preview-FP8 variant alongside the full-weight release. The model is available inside Tencent products including WorkBuddy, CodeBuddy, Yuanbao, and ima, and via API through Tencent Cloud TokenHub and OpenRouter. Tencent listed API pricing at about $0.834 per million input tokens and $2.501 per million output tokens, with a limited free-access window through WorkBuddy and CodeBuddy at launch. Confirm current pricing and access terms on Tencent's own pages before you budget around them.
Tencent reported gains across a set of engineering benchmarks and, in an internal blind evaluation, an average score of 2.99 out of 4.00 across 203 engineering tasks judged by 163 experts — slightly ahead of the GLM 5.3 and Kimi K3 numbers it cited. Because that blind evaluation is Tencent's own, treat it as a vendor claim, not an independent result. The most unusual detail in the announcement is agentic: Tencent says Hy4 participated in optimizing its own training methods, data strategies, and evaluation frameworks, and autonomously tuned its inference system for a reported 31.8% end-to-end throughput improvement.
There are two ways to act on this today. The fast one is to ride the story: paste "Tencent just open-sourced Hy4 preview, a 770B agentic coding model" into [Kompozy](/)'s Quick Ingest and fan that single beat into a Text Post, an X thread, a LinkedIn [Carousel](/glossary/hyperframes), a captioned [Persona Short](/glossary/persona-shorts) explaining what open weights mean for builders, and a blog explainer — then schedule and publish the set across the eight social platforms plus blog and email. Kompozy is a generation-and-publishing engine, so one news item becomes a full cross-platform package the same afternoon.
The more durable move uses Hy4 for what it is actually good at. Point it at a dense source — a long technical transcript, a set of release notes, an earnings call — and let its million-token context return a clean brief or a slate of scripts. Then drop the strongest draft into Kompozy as a source, and Kompozy does the part a text model can't: it generates roughly 25–35 finished assets across 18 formats, rewrites every one under a [Persona Brief](/glossary/persona-brief) so it sounds like you instead of like a raw model, puts a face on the dry material with a HeyGen avatar, and ships the batch through [Autopilot](/glossary/autopilot) behind a per-post review. Hy4 reasons and drafts at the front; Kompozy builds the identity and delivers it to an audience.
Hy4 preview is a large language model released and open-sourced by Tencent Hunyuan on August 28, 2026. It uses a mixture-of-experts architecture with 770 billion total parameters (about 49 billion active per step) and a context window exceeding 1 million tokens, and it is built for software engineering, office and financial analysis, game development, and scientific research.
Tencent published the Hy4 preview model weights openly — along with a lower-precision Hy4 preview-FP8 variant — on Hugging Face, ModelScope, GitCode, and CNB. It is also usable inside Tencent products like WorkBuddy, CodeBuddy, Yuanbao, and ima, and via API through Tencent Cloud TokenHub and OpenRouter. Confirm the exact license terms on Tencent's release pages.
No. Hy4 is a text-in, text-out model focused on coding, reasoning, and analysis — it does not produce images, video, or audio, and it does not publish. To turn its drafts and briefs into finished visual content and posts, pair it with a generation-and-publishing engine like Kompozy, which makes persona/avatar video, carousels, images, blogs, and newsletters and schedules them across platforms.
Tencent listed API pricing at roughly $0.834 per million input tokens and $2.501 per million output tokens, with a limited free-access period through WorkBuddy and CodeBuddy at launch. Prices and access windows can change, so verify current figures on Tencent Cloud before relying on them.