Step 5 Preview is an open-weight model from StepFun for coding, software engineering, and agentic workloads. It uses a sparse Mixture-of-Experts architecture with 600B total / 27B active parameters across 92 layers, with Sparse GQA attention for long context. Context length: 128K tokens. Input: text. Output: text.
On-demand deployments allow you to use Step 5 Preview on dedicated GPUs with Fireworks' high-performance serving stack with high reliability and no rate limits.
