StepFun: Step 5 Preview

Step 5 Preview is a model from StepFun that accepts text, image, and video input and returns text. It offers a 1,000,000-token context window with up to 64,000 completion tokens per response, which leaves room for long documents, extended transcripts, or large batches of material in a single request. It supports tool calling and a reasoning mode; structured output support is not specified, so teams that depend on strict schemas should test before committing. At $1.00 per million input tokens and $2.70 per million output tokens, StepFun's preview sits at a moderate price point, worth shortlisting for multimodal or long-context workloads where input volume drives cost. Its blended benchmark score of 74.2 rests on a single independent benchmark (AI Index 72.2), so its standing is thinly evidenced. Treat it as a candidate to evaluate on your own tasks rather than a proven pick, especially given its preview status.