{"slug": "stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context", "title": "StepFun Releases Step 5 Preview Open Weights: 600B MoE, 27B Active, 1M Context", "summary": "StepFun released Step 5 Preview as open weights, publishing FP8 and BF16 checkpoints on Hugging Face and ModelScope. The sparse Mixture-of-Experts model has 600B total parameters, 27B active per token and up to 1M tokens of context, and StepFun built it for long-horizon agentic work.", "body_md": "StepFun has released Step 5 Preview as open weights. FP8 and BF16 checkpoints are live on Hugging Face and ModelScope. Step 5 Preview is a sparse Mixture-of-Experts model from StepFun built for long-horizon agentic work. It has 600B total parameters, 27B active per token and up to 1M tokens of context. For developers, this is […]\n\nThe post [StepFun Releases Step 5 Preview Open Weights: 600B MoE, 27B Active, 1M Context](https://www.marktechpost.com/2026/10/16/stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context/) appeared first on [MarkTechPost](https://www.marktechpost.com).", "url": "https://wpnews.pro/news/stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context", "canonical_source": "https://www.marktechpost.com/2026/10/16/stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context/", "published_at": "2026-10-17 06:29:55+00:00", "updated_at": "2026-10-17 08:33:11.500817+00:00", "lang": "en", "topics": ["artificial-intelligence", "large-language-models", "ai-agents", "ai-research"], "entities": ["StepFun", "Step 5 Preview", "Hugging Face", "ModelScope"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context", "markdown": "https://wpnews.pro/news/stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context.md", "text": "https://wpnews.pro/news/stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context.txt", "jsonld": "https://wpnews.pro/news/stepfun-releases-step-5-preview-open-weights-600b-moe-27b-active-1m-context.jsonld"}}