600B open weights, trained for long-running agents
Step 5 Preview is StepFun's open-weight MoE for coding, financial research and long-running agents. It has 600B total parameters, 27B active per token and a 1M-token context, with deployment support for vLLM, SGLang and Transformers.
Step 5 Preview launched on Product Hunt on 2026-10-17 and has 83 upvotes and 8 comments so far.
Pricing details for this tool haven’t been verified yet — check the tool’s website for current plans.