Step 5 Preview

step-5-preview

Step 5 Preview is StepFun’s flagship model for complex reasoning, software engineering, and multi-step agent workflows. With native support for text, image, and video input and a 1-million-token context window, it can analyze extensive documents, codebases, charts, and visual content within a single request. Built for practical problem-solving, the model supports tool calling, structured outputs, and adjustable reasoning effort. Its strengths span coding, research, and professional knowledge work, with particular emphasis on financial analysis. Step 5 Preview is a strong choice for applications that need to combine information from multiple sources and work toward detailed, actionable results.

Context Window

1M tokens

Maximum Output

1M tokens

Release Date

Sep 16, 2026

Modalities

Step 5 Preview Pricing

Input PriceOutput PriceCache Read
$1/M$2.7/M$0.05/M

Step 5 Preview API Capabilities

Reasoning

Supported

Tool calling

Supported

Temperature parameter

Not supported

Attachments

Supported

Knowledge Base

—

Endpoint Protocols

Completions APIResponses APIMessages API

Model Highlights

Verified strengths and model characteristics.

Sparse Expert Architecture

A 600B-parameter MoE activates 27B parameters per token, limiting active computation.

Long Context With Vision

A 1M-token context window and image input support work across extensive text and visual material.

Sustained Agentic Work

Official demonstrations show iterative engineering that uses prior results and execution feedback to guide further work.

Use Cases

Practical workloads supported by official examples.

Software Engineering

Implement features, fix bugs, and refine interactive applications through repeated execution and feedback.

Research Deliverables

Collect and reconcile sources, then produce analytical workbooks or reports with traceable evidence.

Financial Analysis

Reconcile financial reports and draft valuation analyses with explicit assumptions and reproducible calculations for expert review.

How to Use Step 5 Preview via the TokenHub API

Create API key
import OpenAI from "openai"

const client = new OpenAI({
  apiKey: process.env.TOKENHUB_API_KEY,
  baseURL: "https://us-api.tokenhub.com/v1",
})

const result = await client.chat.completions.create({})
console.log(result.choices[0]?.message?.content)

Step 5 Preview Benchmarks

Step 5 Preview

Index score
Artificial Analysis Intelligence IndexArtificial Analysis broad capability aggregate43.7

Metrics sourced from Artificial Analysis

Step 5 Preview Media and Demos

Verified public announcements, demonstrations, and community discussions.

X (Twitter)

Step 5 Preview: Official Launch

StepFun

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Step 5 Preview: OpenRouter And Coding Integrations

StepFun

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Step 5 Preview: OpenCode Trial Announcement

OpenCode

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Reddit

Step 5 Preview: Community Launch Overview

techspecsmart

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Step 5 Preview: Command Code Availability

maedahbatool

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Step 5 Preview: Architecture And Weight-Release Discussion

adefa

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YouTube

Step 5 Preview: Coding And Reasoning Tests

AICodeKing

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Watch on YouTube

Step 5 Preview: Interactive Application Review

AI产品狙击手 kzhu

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Watch on YouTube

Step 5 Preview: Agentic And Finance Demonstration

Code With Yousaf

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Watch on YouTube

FAQs

Model selection, limitations, and access.

What Is Step 5 Preview?+

StepFun’s flagship preview model combines sparse MoE architecture, a 1M-token context, and vision for coding and professional work.

Which Workloads Suit Step 5 Preview?+

Consider software changes, research reports, analytical workbooks, and financial analysis requiring multiple rounds of evidence gathering and refinement.

What Tradeoffs Should Guide Model Selection?+

StepFun reports remaining weaknesses on its hardest, longest engineering tasks. Compare task success, latency, and total token cost on representative workloads.

How Do I Use Step 5 Preview Through TokenHub?+

Check that your TokenHub account lists the model, then use its documented model ID, endpoint, and credentials. Provider availability does not confirm TokenHub routing.

Is Step 5 Preview Available, and What Does It Cost?+

As of October 9, 2026, StepFun offers product and API access and schedules open weights for October 15. Check TokenHub for its own current rates and availability.

Ready to use Step 5 Preview?

Use one API key to access Step 5 Preview and more AI models through TokenHub.

Create API key