Step 5 Preview
Summary
Step 5 Preview is a proprietary language model from StepFun, released on 16 Sept 2026. It accepts text and images and generates text, with a 1M-token context window and up to 1M output tokens per response. As of 4 Oct 2026, the lowest listed API price is $1 per million input tokens and $2.70 per million output tokens (Vercel AI Gateway), across 1 provider we track.
StepFun flash model for efficient multimodal reasoning, coding, and tool use
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | StepFun |
|---|---|
| Release date | 16 Sept 2026 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 1M (1,000,000 tokens) [models.dev] |
| Max output | 1M tokens [models.dev] |
| Input | Text and images [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | No [models.dev] |
| Tool calling | No [models.dev] |
| Structured output | Yes [models.dev] |
Step 5 Preview API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| Vercel AI Gateway stepfun/step-5-preview | $1 | $2.70 | $0.05 | 1M | models.dev, 4 Oct 2026 |
Frequently asked questions
What is the context window of Step 5 Preview?
Step 5 Preview has a context window of 1,000,000 tokens (1M) and can generate up to 1,000,000 tokens in a single response, according to models.dev.
How much does the Step 5 Preview API cost?
Step 5 Preview is listed from $1 per million input tokens and $2.70 per million output tokens (Vercel AI Gateway). Prices last verified 4 Oct 2026.
Is Step 5 Preview open source?
No. Step 5 Preview is a proprietary model; StepFun has not released its weights. It is available through APIs including Vercel AI Gateway.
When was Step 5 Preview released?
StepFun released Step 5 Preview on 16 Sept 2026, according to models.dev.
Change history
No changes detected since we started tracking this model. We re-check every source daily.