Model overview
Reasoning models are designed for deep analytical work, including logic, mathematics, coding, and other complex tasks.Models
A model’s context length limits the total input and output it can process in one request. See each model overview for its exact rules.
Get started with reasoning models
Developer guides
Reasoning model guide
Learn recommended patterns for complex tasks, tool calling, and long-context work.
Migrate from OpenAI
Move an OpenAI-compatible integration to StepFun with minimal changes.
Build multi-turn conversations
Manage message history and context for stable multi-turn experiences.
Output JSON
Return machine-readable structured JSON for application integration.
Stream responses
Render output as it arrives to reduce perceived wait time.
Use tool calling
Let a model call search, databases, or business functions.
Prompt caching
Reuse repeated context to lower cost and improve response time.