StepFun Launches Step 5 Preview: A 600B-Total, 27B-Active MoE Model With 1M Context for Long-Horizon Agentic Work

StepFun has released Step 5 Preview, a sparse Mixture-of-Experts model with 600B total parameters and 27B active per token. It supports a 1M-token context window and accepts text, image, and video input. The model targets long-horizon agentic work in software engineering, professional knowledge work, and finance. API access is live at $1.00 per 1M input tokens and $2.70 per 1M output tokens, and open weights are scheduled for October 15, 2026. The post StepFun Launches Step 5 Preview: A 600B-Total, 27B-Active MoE Model With 1M Context for Long-Horizon Agentic Work appeared first on MarkTechPost.

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