Step 5 Preview via the Tokenator API

What the model is for

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. It is designed for extended tasks that span large codebases and documents, using tools and refining results over multiple steps.

Specification

Full nameStep 5 Preview
API IDstep-5-preview
Model vendorStepFun
TypeText model (chat / completions)
Context window1.05M tokens
Max output131.1K tokens
Image inputyes
Tokenator usage multiplier1.2×
Input modalitiestext, image
Aliasescursor-step-5-preview
Supported API formats/v1/chat/completions /v1/responses /v1/messages
Upstream providers1
Current statusavailable
Data updated2026-11-02

Benchmarks

Intelligence index28.5

Artificial Analysis data loaded into the catalog for this model.

Upstream providers

ProviderMultiplier
AiPartners Ltd1.2×

A request goes to the first available provider by priority; if it fails, Tokenator switches to the next one.

Example request

curl
curl https://api.tokenator.top/v1/chat/completions \
  -H "Authorization: Bearer sk-your-tokenator-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "step-5-preview",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Compatible tools

The model can be used in any tool that accepts a custom base URL: Claude Code, Codex CLI, OpenCode, Cursor, Cline, Kilo Code, Cherry Studio, DeepSeek Harness, Hermes, Pi, OpenClaw.

FAQ about Step 5 Preview

What is the API ID of Step 5 Preview?

step-5-preview — put this into the model field of your request.

What context window does Step 5 Preview have?

1.05M tokens; max output is 131.1K tokens.

How many tokens will a request cost?

(input + output) × 1.2×. See the documentation for details.

Which tools support this model?

Any tool that accepts a custom base URL: Claude Code, Codex CLI, OpenCode, Cursor, Cline, Kilo Code. Setup guides are in the integrations section.