StepFun open-sources Step 5 Preview: 600B MoE with 1M context, No. 2 on OpenRouter
Dr_Singularity · x · 2026-10-15
StepFun released the open weights for Step 5 Preview on October 15, along with a technical blog on its architecture.
- Architecture: sparse MoE with 600B total parameters, 27B active per token, up to 1M token context, accepting text, image and video input
- Design goal: built for long-horizon agent tasks — it can compress its progress and continue when the context fills up, targeting long coding and research workloads
- Traction: StepFun says it performs well in coding, software engineering, professional knowledge work and finance, and currently ranks No. 2 worldwide on OpenRouter's weekly and daily usage charts
Related event: StepFun Open-Sources Step 5 Preview: 600B MoE with 1M Context(16 posts)→
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