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
Quickstartfor 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 #
-
Create an API key on the StepFun Open Platform.
-
Open the Quickstart , select Step 5 Preview, and switch between the text chat, image understanding, and video understanding examples.
-
Send a request with cURL or Python and read the result from
choices[0].message.content. -
Before going live, use the API reference 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
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)