Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters).
Prices update automatically — checked daily against provider list prices.
Independent benchmark scores for Step 5 Preview, measured by Artificial Analysis. Higher is better.
Step 5 Preview is a commercial AI model by Stepfun. The specifications below are tracked automatically: pricing is refreshed daily from public list prices, so the numbers on this page reflect the current cost of using the model through its API.
Step 5 Preview is an AI language model from Stepfun. It is a proprietary model, available through an API. It scores 43.7 on the Artificial Analysis intelligence index.
Step 5 Preview is not free: it costs $1 per million input tokens and $2.7 per million output tokens. Open-weight alternatives can be self-hosted at no per-token cost.
Independent benchmarks from Artificial Analysis give it Humanity's Last Exam 46.5%, Long Context Reasoning 88.3%, SciCode 58.9%.
It generates about 90.2 tokens per second, with a median 1.79s delay before the first token. Measured independently by Artificial Analysis.