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
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.
Tools, search, and code execution capabilities are provided by the application that integrates the model; the model does not itself access your local environment or external services.
Input and output
Image and video input
See the Quickstart for image and video request examples. For complete limits, see Image understanding best practices and Video understanding best practices.
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.
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.
More information
Quickstart · API reference · Claude Code integration · Pricing and Rate Limits