Tencent Hy4 Preview LLM

Tencent's Hy Team released Hy4 preview, a 770B-parameter Mixture-of-Experts flagship model with 49B activated parameters per token, featuring Gated DeepSeek Sparse Attention and a 1M context length. The model, built with input from Tencent engineers, game developers, and finance analysts, outperformed prior models in internal blind evaluations on 203 engineering tasks, positioning it at the open-source frontier.

中文 /Tencent-Hunyuan/Hy4-preview/blob/main/README CN.md ｜ English 🖥️ Official Website https://aistudio.tencent.com/ | 💬 GitHub Model Introduction model-introduction A New Flagship Generation a-new-flagship-generation Built for Productivity built-for-productivity Benchmark Appendix benchmark-appendix Known Limitations known-limitations News news Model Links model-links Quickstart quickstart Deployment deployment Finetuning finetuning Quantization quantization License license Contact Us contact-us Hy4 preview is a new-generation Mixture-of-Experts MoE flagship model developed by the Tencent Hy Team. The model comprises 770B total parameters, of which 49B are activated per token. The backbone consists of 78 layers, where the first layer uses a standard dense FFN and the remaining 77 layers replace it with MoE, each containing 256 routed experts and 1 shared expert; every token activates the top-8 routed experts along with the shared expert. In addition to the backbone, 1 native MTP layer 10B total parameters, 0.7B activated is built in for speculative decoding. On the architecture side, inspired by DeepSeek and GLM, the attention module employs Gated DeepSeek Sparse Attention https://arxiv.org/abs/2512.02556 Gated DSA with IndexCache https://arxiv.org/abs/2603.12201 for cross-layer sparse index reuse. The residual pathway uses iHC identity Hyper-Connections https://zhuanlan.zhihu.com/p/2010852389670908320 to expand inter-layer information flow. The table below lists backbone parameters only, excluding the MTP layer. | Property | Value | |---|---| | Architecture | Mixture-of-Experts MoE | | Total Parameters | 770B | | Activated Parameters | 49B | | Layers | 78 | | Hidden Size | 6144 | | Attention Type | Gated DSA | | Attention Heads | 64 | | Query Compression Dimension | 2048 | | Key-Value Compression Dimension | 512 | | Indexer Heads / Head Dimension | 32 / 128 | | Indexer top-k | 2048 | | Residual Streams | 4 | | Routed Experts | 256 | | Shared Experts | 1 | | Activated Routed Experts per Token | 8 | | MoE Intermediate Size | 2048 | | FFN Intermediate Size | 18432 | | Context Length | 1M | | Vocabulary Size | 120832 | We scaled Hy4 preview on three fronts: model size, context length, and training data. Stronger pre-training and a substantially larger post-training run compound into another step change in capability — the largest generation-over-generation gain we've measured, and enough to put Hy4 preview at the open-source frontier. We partnered with top experts inside Tencent — such as software engineers, game developers, finance analysts, and security experts — and built training data around the work they ship. The result is a model that gets meaningfully further on the tasks these teams run every day: Software engineering : Better at understanding, planning, debugging, and verifying long-horizon development tasks, with further gains in the visual taste and interaction quality of front-end work. Office and analysis : Takes messy context spread across many files and converts it into shareable artifacts — documents, spreadsheets, and presentations — handling data analysis, equations, and financial models with greater precision. Game development : Turns a single prompt into a playable prototype and works fluently with game engines, so developers can keep refining complex projects over multiple turns. Scientific research : Stronger understanding, reasoning, and problem-solving on hard research questions, with solid progress across AI research, molecular dynamics, condensed matter physics, and pure mathematics. We also continue to co-design Hy4 preview with Tencent products like CodeBuddy and WorkBuddy, so that gains in the model show up in the work people actually do with it. To check that, we ran a blind side-by-side evaluation: 163 internal experts rated model outputs on 203 engineering tasks. Hy4 preview came out slightly ahead of both GLM 5.3 2.99 vs. 2.92 average, 46.8% wins / 12.8% ties / 40.4% losses and Kimi K3 2.99 vs. 2.94, 51.2% wins / 7.9% ties / 40.9% losses . This is an early version of Hy4. There is real headroom left in both pre-training and post-training, and we are shipping with known issues — among them, spending longer than necessary reasoning through complex tasks, and a tendency to over-verify its own work. We'll keep iterating quickly on these. As with Hy3 preview, we would rather ship early and hear what breaks — that's what made Hy3 substantially better, and it's how we will get Hy4 right. We will also keep collaborating closely with Tencent's products and in-house experts to push the boundaries of model intelligence while making it more abundant and affordable. - 🔥 We open-source Hy4 preview and Hy4 preview-FP8 model weights on Hugging Face https://huggingface.co/tencent/Hy4-preview , ModelScope https://modelscope.cn/models/Tencent-Hunyuan/Hy4-preview , GitCode https://ai.gitcode.com/tencent hunyuan/Hy4-preview , and CNB https://cnb.cool/ai-models/tencent/Hy4-preview . | Model Name | Description | Hugging Face | ModelScope | GitCode | CNB | |---|---|---|---|---|---| | Hy4 preview | Instruct model | 🤗 | Model https://modelscope.cn/models/Tencent-Hunyuan/Hy4-preview Model https://ai.gitcode.com/tencent hunyuan/Hy4-preview Model https://cnb.cool/ai-models/tencent/Hy4-preview Model https://huggingface.co/tencent/Hy4-preview-FP8 Model https://modelscope.cn/models/Tencent-Hunyuan/Hy4-preview-FP8 Model https://ai.gitcode.com/tencent hunyuan/Hy4-preview-FP8 Model https://cnb.cool/ai-models/tencent/Hy4-preview-FP8 Deploy Hy4 preview with vLLM vllm or SGLang sglang first, then call the OpenAI-compatible API: python from openai import OpenAI client = OpenAI base url="http://127.0.0.1:8000/v1", api key="EMPTY" response = client.chat.completions.create model="hy4-preview", messages= {"role": "user", "content": "Hello Can you briefly introduce yourself?"}, , temperature=0.9, top p=1.0, print response.choices 0 .message.content Recommended parameters: temperature=0.9 , top p=1.0 . Reasoning mode: Defaults to "high" deep chain-of-thought , which suits complex tasks such as math, coding, and reasoning. For direct responses, pass extra body={"chat template kwargs": {"reasoning effort": "no think"}} . See the Deployment deployment section below for how to start the API server. For production serving, we recommend using vLLM https://github.com/vllm-project/vllm or SGLang https://docs.sglang.io/ . Please refer to the recipes: Use official prebuilt image vllm/vllm-openai:hy4-preview : docker run --gpus all \ -p 8000:8000 \ --ipc=host \ -v ~/.cache/huggingface:/root/.cache/huggingface \ vllm/vllm-openai:hy4-preview tencent/Hy4-preview-FP8 \ --tensor-parallel-size 8 \ --speculative-config '{"num speculative tokens":3,"method":"mtp"}' \ --attention-backend FLASHMLA SPARSE \ --tool-call-parser hy v4 \ --reasoning-parser hy v4 \ --enable-auto-tool-choice \ --port 8000 \ --served-model-name hy4-preview Use the official prebuilt image lmsysorg/sglang:hy4-preview multi-arch, x86 and Arm : docker pull lmsysorg/sglang:hy4-preview docker run --gpus all --ipc=host -p 8000:8000 lmsysorg/sglang:hy4-preview \ python3 -m sglang.launch server \ --model tencent/Hy4-preview-FP8 \ --tp-size 8 \ --reasoning-parser auto \ --tool-call-parser auto \ --speculative-algorithm NEXTN \ --speculative-num-steps 3 \ --speculative-eagle-topk 1 \ --speculative-num-draft-tokens 4 \ --port 8000 \ --served-model-name hy4-preview Hy4 preview provides a complete model finetuning pipeline. For detailed documentation, please refer to: Finetuning Guide /Tencent-Hunyuan/Hy4-preview/blob/main/finetune/README.md We provide AngelSlim https://github.com/tencent/AngelSlim , a more accessible, comprehensive, and efficient toolkit for large model compression. AngelSlim supports a comprehensive suite of compression tools for large-scale multimodal models, including common quantization algorithms, low-bit quantization, and speculative sampling. Hy4 preview is released under the Apache License 2.0 . See LICENSE /Tencent-Hunyuan/Hy4-preview/blob/main/LICENSE for details. If you have any questions or suggestions, feel free to reach out to our R&D and product teams via email: 📧 hunyuan opensource@tencent.com mailto:hunyuan opensource@tencent.com Hy4 preview is developed by the Tencent Hy Team.