StepFun: Step 5 Preview

proprietary

Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters).

Context
1.0M
Max output
64K
Input price
$1/1M tokens
Output price
$2.7/1M tokens

Capabilities

Reasoning & Interaction
Reasoning
Tool Calling
Output Control
Structured Output
JSON Mode

Details

Model IDstepfun/step-5-preview
Provider OpenRouter
Creator StepFun
Family—
Licenseproprietary
Status—
Type—
Input modalitiestext, image, video
Output modalitiestext
Open weightNo
Parameters—
Architecture—
Context window1.0M tokens
Max input—
Max output64K tokens
Reasoning tokens—
Knowledge cutoff—
Release date
Sourceofficial

Tools

Function Callingfunction_calling
Call external functions and APIs

Pricing

Input
$1
Output
$2.7
Cache write
—
Cache read
$0.1
Batch in
—
Batch out
—

API

GET/v1/models/openrouter/stepfun/step-5-preview

StepFun: Step 5 Preview

stepfun/step-5-preview

Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters).

Changes · 4 entries
stepfun/step-5-previewcreateca7a400Nov 2, 2026, 03:02 AM
stepfun/step-5-previewupdatebcf2693Oct 16, 2026, 06:36 AM
pricingcached input$0.05→$0.1
stepfun/step-5-previewupdateb92059eOct 15, 2026, 06:37 AM
context_window1000000→1048576
stepfun/step-5-previewcreate70614e7Oct 9, 2026, 06:39 AM