Everything about Hy4 preview

What you need to know

Hy4 preview is a language model from Tencent (Hunyuan), released on August 28, 2026. That makes it 2 months old as of October 22, 2026. It is an open-weight model: you can host it yourself on infrastructure you control, and 19 API providers listed on models.dev also offer it. It has a reasoning mode: it can "think" before answering, which helps with multi-step problems but uses more tokens, and therefore more money.

We file it under open-weight models (68 models in this category on the site).

How much does Hy4 preview cost?

Hy4 preview costs $0.83 per million input tokens and $2.5 per million output tokens (median of 19 providers, checked on October 22, 2026).

In practice, an agent task that reads 20,000 tokens and writes 2,000 costs about $0.022, or $21.68 for 1,000 such tasks.

That is 2.5 times the median output price of open-weight models ($1).

To estimate your own budget, use the agent cost calculator.

What do independent benchmarks say?

As of October 22, 2026, Epoch AI publishes no score for Hy4 preview on our basket's benchmarks. To place it, rely on its specifications and price, then test it on your own cases.

Technical specifications

Its context window reaches 1,000,000 tokens, roughly 1,500 pages of text at 500 words per page: enough to load a whole book or a mid-sized codebase. A single answer can run to 64,000 tokens.

It accepts as input: text.

It can call tools (functions, APIs) and return structured JSON output, which makes it a possible foundation for an AI agent.

The weights are published on Hugging Face (tencent/Hy4-preview). See also our list of open-source models.

Who is it for?

Given its category, Hy4 preview is mainly aimed at projects where you want control over your data or hosting, or want to adapt the model to your field.

Its very large context window makes it worth considering for analysing large sets of documents in a single request.

Before adopting it, test it on your own examples: benchmarks measure standard tasks, not your job.

Alternatives

In the same category, the models closest to Hy4 preview are:

• Kimi K2 Thinking (Moonshot AI, index 69.6)
• Kimi K2 0905 (Moonshot AI, $2.5 per million output tokens)
• Nemotron 3 Ultra 550B A55B (NVIDIA, $2.4 per million output tokens)
• GLM-5 (Zhipu AI (Z.ai), index 77.2)