Model reference · open weights

Hy4

Hy4 is an open-weight language model from tencent, listed in the AxForge catalogue. AxForge can bring it up on EU-owned hardware for you on request — with the licence handled where one is required.

NEW · released this week LLMs tencent 2 variants 2k downloads/mo
Request this model on EU hardware All served models Not on the shared API today — deployed on request.

About

What Hy4 is

[](#license) &nbsp;&nbsp; [](https://huggingface.co/tencent/Hy4-preview) &nbsp;&nbsp; [](https://modelscope.cn/models/Tencent-Hunyuan/Hy4-preview) &nbsp;&nbsp; [](https://cnb.cool/ai-models/tencent/Hy4-preview) &nbsp;&nbsp; [](https://ai.gitcode.com/tencenthunyuan/Hy4-preview) 🖥️&nbsp;<a href="https://aistudio.tencent.com/"<bOfficial Website</b</a&nbsp;&nbsp;|&nbsp;&nbsp; 💬&nbsp;<a href="https://github.com/Tencent-Hunyuan/Hy4-preview"<bGitHub</b</a</p Table of Contents - Model Introduction - A New Flagship Generation - Built for Productivity - Benchmark Appendix - Known Limitations - News - Model Links - Quickstart - Deployment - vLLM - SGLang - Finetuning - Quantization - License - Contact Us Model Introduction 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 (Gated DSA) with IndexCache for cross-layer sparse index reuse. The residual pathway uses iHC (identity Hyper-Connections) to expand inter-layer information flow. Model Specifications The table below lists backbone parameters only, excluding the MTP layer. A New Flagship Generation 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. Built for Productivity We partnered with top experts inside Tencent — such as software engineers, game developers, finance analysts, and security experts — and built training dat

Summarised from the published model card. Read the full card on the HuggingFace links below.

Specifications

What it is

Makertencent
TypeLanguage models
Parameters (lead)780.0B
Variants2
Runs withtransformers
Released2026-08-27
Popularity2k downloads / month
Likes316
LicenceOpen weights

How it works

How language models work

Your prompttext / messagesTransformerattention over tokensNext-token loopgenerate + streamResponsetext · tool callsA language model reads your tokens and predicts the next one, again and again, streaming the reply back.

Variants

Sizes & precisions

Open weights ship in several sizes and precisions. One page, all the variants — pick the one that fits your GPU. VRAM figures are estimates from model size.

VariantParamsPrecisionVRAMFits 16 GBWeights
Hy4-preview780.0BBF16~1793.9 GBWeights ↗
Hy4-preview-FP8803.5BFP8~924 GBWeights ↗

Using it via the API

Call it like any OpenAI endpoint

Once AxForge deploys hy4 for you, it answers on the OpenAI-compatible API — the same base URL and keys as every other model. (hy4 below is illustrative; you get the exact model name on deployment.)

$ curl -sS https://api.axforge.ai/v1/chat/completions \
  -H "Authorization: Bearer $AXFORGE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"hy4","messages":[{"role":"user","content":"Hello"}]}'

Details

Languages, data & research

Tags

transformers safetensors hy_v4 text-generation hunyuan hy4 moe conversational eval-results endpoints_compatible fp8 quantized modelopt

Papers

Licence

Open weights

Open weights under apache-2.0 — commercial use is permitted. Deploy it on AxForge EU hardware on request. Read the licence ↗

Sources

Weights & code

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