# Step 5 Preview

> 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.

Source page: https://www.aimodel.directory/models/step-5-preview
Last verified: 4 Oct 2026

## Specifications

- **Developer:** StepFun
- **Release date:** 16 Sept 2026 (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Status:** Generally available (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Weights:** Proprietary (API only) (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Context window:** 1M (1,000,000 tokens) (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Max output:** 1M tokens (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Input:** Text and images (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Output:** Text (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Reasoning mode:** No (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Tool calling:** No (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)
- **Structured output:** Yes (source: models.dev, https://github.com/sst/models.dev/blob/dev/providers/vercel/models/stepfun/step-5-preview.toml)

## API pricing (USD per 1M tokens)

| Provider | Input | Output | Cached input | Context |
|---|---|---|---|---|
| Vercel AI Gateway | $1 | $2.70 | $0.05 | 1M |

## FAQ

### 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.

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Data licensed CC BY 4.0. Cite as: AI Model Directory, "Step 5 Preview", https://www.aimodel.directory/models/step-5-preview