FAMILY • 2 MODELS
StepFun
Every StepFun model reviewed in the directory.
Browse all model families →Top picks
StepFun's 600B open-weight model for long-running agents, with a 1M-token context
Step 5 Preview is StepFun's flagship model, published as downloadable weights on October 15, 2026 after an earlier hosted release. It is a sparse mixture-of-experts model with about 600 billion total parameters and 27 billion active per token, takes text and images as input, returns text, and supports up to one million tokens of context, aimed at coding and long professional work. Weights ship in BF16 and FP8 under the StepFun Model License 1.0, which StepFun describes as Apache-2.0-style with additional attribution and commercial-licence conditions. The model card gives example deployments...
Freemium
Best Large Open Agent Model
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StepFun's 198B MoE vision-language model
StepFun Step 3.7 Flash is a 198-billion-parameter mixture-of-experts vision-language model released on May 28-29, 2026. It supports text, image, and video understanding with a focus on efficient inference and strong multimodal reasoning.
Freemium
Best for Efficient VLM
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All models
| Model | Release date | Pricing | Modalities | Best For | Link |
|---|---|---|---|---|---|
| Step 5 Preview | Oct 19, 2026 | Freemium | LLMs, Multimodal Reasoning | Best Large Open Agent Model | View → |
| StepFun Step 3.7 Flash | May 29, 2026 | Freemium | LLMs, Multimodal Reasoning | Best for Efficient VLM | View → |