# Step 5 Preview: StepFun's frontier model with 1M context and video input

> Source: <https://platform.stepfun.ai/docs/en/guides/models/step-5-preview>
> Published: 2026-09-21 13:43:22+00:00

**Step 5 Preview is StepFun’s flagship model for agentic work.** It delivers frontier-level performance across software engineering and professional knowledge work, with particular strength in finance. It natively supports text, image, and video input and provides a

**1M-token context window**, making it suitable for tasks that require large amounts of information, tool calls, and continuous progress toward a deliverable.

## At a glance

## Core capabilities

## Long-context understanding and reasoning

Analyze long documents, multiple source materials, and conversation history within a 1M-token context.

**Typical tasks**: cross-document question answering and research material organization.
## Programming and software engineering

Work across multiple programming languages and engineering tasks, with tools to advance development, modification, and verification.

**Typical tasks**: troubleshooting, code changes, and test creation.
## Multi-step Agent tasks

Use tools provided by an application to retrieve information, process documents, and continue through multi-step work.

**Typical tasks**: deep research and analytical reporting.
## Multimodal understanding

Combine images, video, and text to extract and analyze multimodal information.

**Typical tasks**: chart analysis, screenshot question answering, and video summarization.
## Use cases

- **Software development** : Combine code, dependency information, and error logs to locate problems, modify code, and recommend tests.
- **Long-document processing** : Organize multiple sources in a long context, extract and summarize information, and cross-check details.
- **Research and analysis** : Work with search, code execution, or document tools to break down tasks and produce structured results.
- **Multimodal understanding** : Analyze screenshots, charts, and video, and output conclusions in a specified format.

## Input and output

### Image and video input

See the 

[Quickstart](https://platform.stepfun.ai/docs/en/quickstart/overview)for image and video request examples. For complete limits, see

[Image understanding best practices](https://platform.stepfun.ai/docs/en/guides/developer/image-chat)and

[Video understanding best practices](https://platform.stepfun.ai/docs/en/guides/developer/video-chat).

## Features and configuration

## Integration

1. Create an API key on the StepFun Open Platform.
2. Open the [Quickstart](https://platform.stepfun.ai/docs/en/quickstart/overview) , select Step 5 Preview, and switch between the text chat, image understanding, and video understanding examples.
3. Send a request with cURL or Python and read the result from `choices[0].message.content` .
4. Before going live, use the [API reference](https://platform.stepfun.ai/docs/en/api-reference/chat/chat-completion-create) to add timeout, retry, error-handling, and key-management logic.

## Quickstart

See text, image, and video request examples.

## Chat Completions API

See the complete request parameters, response fields, and usage information.

## Claude Code integration

Configure Step Plan and enable 1M context.

## Pricing and rate limits

Step 5 Preview is billed based on actual input and output token usage. For current prices, cache billing rules, and account rate limits, see
[Pricing and Rate Limits](https://platform.stepfun.ai/docs/en/guides/pricing/details#pricing-for-multimodal-reasoning-models).

## More information

[Quickstart](https://platform.stepfun.ai/docs/en/quickstart/overview)·

[API reference](https://platform.stepfun.ai/docs/en/api-reference/chat/chat-completion-create)·

[Claude Code integration](https://platform.stepfun.ai/docs/en/step-plan/integrations/claude-code)·

[Pricing and Rate Limits](https://platform.stepfun.ai/docs/en/guides/pricing/details)