Step 5 Preview

Chat Completions

step-5-preview

StepFun|Created Oct 17, 2026|1.0M context

Chat Completions

Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters). It performs strongly in software engineering and professional knowledge work, with particular strength in finance.

Overview Specifications Activity Performance Uptime Examples API Reference

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Pricing-50%

Pay-as-you-go rates for this model. More details in the billing guide.

Input Tokens (1M)

$0.50

Cached Input Tokens (1M)

$0.02

Output Tokens (1M)

$1.35

Capabilities

Input Modalities

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Output Modalities

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Supported Parameters

Available parameters for API requests

Frequency PenaltyLogprobsMax Completion TokensParallel Tool CallsPresence PenaltyReasoning EffortResponse FormatStopTemperatureTool ChoiceToolsTop PLogit Bias