# StepFun Posts Step-5-Preview Vision-Language Model

> The Chinese AI lab's early look at its next multimodal system arrives on Hugging Face ahead of a full release.

Published by The Open Weights on Sep 20, 2026. Canonical: https://theopenweights.com/news/step-5-mgqb

## Key facts

- Company: StepFun
- Model: Step-5-Preview
- Version: 5-Preview
- Category: Vision-Language
- Modalities: Text / LLM, Vision-Language
- License: Other (Open weights, commercial use allowed)
- Context window: 1.0M tokens
- Architecture: Step5ForConditionalGeneration
- Precision: FP8
- Weights size: 644 GB
- Significance: notable
- Published: 2026-09-20
- Last verified: 2026-10-20
- Hugging Face: https://huggingface.co/stepfun-ai/Step-5-Preview
- Canonical URL: https://theopenweights.com/news/step-5-mgqb

StepFun has quietly posted **Step-5-Preview**, an early build of its next-generation vision-language model, on [Hugging Face](https://huggingface.co/stepfun-ai/Step-5-Preview). As the name suggests, this is a preview rather than a finished release, giving researchers and developers an initial window into the direction of the company's Step-5 family.

The model is multimodal, handling both image and text inputs, with vision-language understanding as its primary focus. StepFun has not published detailed specifications alongside the preview, including parameter counts, context length, or benchmark results, so the model's precise capabilities remain to be measured by the community.

## Why it matters

StepFun is among a growing group of Chinese labs releasing increasingly capable multimodal systems into the open ecosystem. Preview drops like this one serve a few purposes:

- They let external developers kick the tires before a stable version lands.
- They signal a lab's technical roadmap to the wider research community.
- They invite early feedback that can shape the eventual general release.

The model carries a custom license rather than a standard permissive one, so teams considering it for production should read the terms on the [model page](https://huggingface.co/stepfun-ai/Step-5-Preview) closely. As a preview, it is best treated as an experimental artifact — a sign of what StepFun intends to ship, with the full Step-5 release still to come.

## Get the model

- [Hugging Face](https://huggingface.co/stepfun-ai/Step-5-Preview)

## Sources

- [stepfun-ai/Step-5-Preview](https://huggingface.co/stepfun-ai/Step-5-Preview) — Hugging Face, Sep 20, 2026

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Source: The Open Weights (https://theopenweights.com/). Aggregated and written by Claude, curated by humans. Cite as: "StepFun Posts Step-5-Preview Vision-Language Model", The Open Weights, Sep 20, 2026, https://theopenweights.com/news/step-5-mgqb