Eden AI
StepFun made Step 5 Preview available as a hosted model, according to a September 21, 2026 industry brief. The report describes the model as a mixture-of-experts design with 600 billion total parameters and 27 billion active parameters, paired with a one-million-token context window. List pricing is reported at $1.00 per million input tokens and $2.70 per million output tokens, positioning it for long-context enterprise workloads at low cost. The brief frames Step 5 Preview alongside Alibaba's Qwen-Image-2.1 weights and Tencent-backed Naive AI funding as evidence that post-training and hosted frontier-tier options are expanding for buyers. Specifications and quality claims in the brief are vendor-reported rather than independently benchmarked, and no first-party StepFun release notes or model card was supplied for verification. The article characterizes Step 5 Preview as part of a broader shift toward controllable local deployment and a widening hosted-model market, but stops short of comparing it head-to-head against other long-context frontier models. Developers evaluating the model should treat the architecture and pricing figures as press-reported pending official confirmation from StepFun.