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).
Model by StepFun
Install
Pick your client. Read the repository before you give any tool access to your data.
{
"model": "stepfun/step-5-preview",
"baseURL": "https://openrouter.ai/api/v1"
}OpenAI-compatible API: point any OpenAI SDK at the base URL and use this model id.
Settings it needs
OPENROUTER_API_KEYrequiredsecret
Get the weekly diff
The weekly diff: one email a week with new agent tools, notable updates and grade changes, plus security alerts for tools you follow. Double opt-in, one-click unsubscribe.
About
Use cases: code-generation, model-inference
Reviews
Write a reviewNo reviews yet. Installed it? Reviews come from verified installers only. How reviews work
Price and limits
| Variant | Input $/M tokens | Output $/M tokens | Cached input $/M |
|---|---|---|---|
| Standard | $1 | $2.7 | $0.1 |
Price as of Oct 26, 2026 from OpenRouter. Prices change often; check before you rely on one.
- Provider
- StepFun
- Model id
stepfun/step-5-preview- Context window
- 1,048,576 tokens (1M)
- Max output
- 64,000 tokens
- Input
- text, image, video
- Output
- text
- Tool calling
- Yes
- Structured outputs
- Yes
- Reasoning
- Yes
- Weights
- Open: stepfun-ai/Step-5-Preview
- Released
- Oct 8, 2026
Details
- Auth
- API key
- License
- License unknown
- First seen
- Oct 24, 2026
- Last checked
- Oct 26, 2026
- Source
- OpenRouter
More from StepFun
- 0.681score
Step 3.5 Flash
StepFun
Step 3.5 Flash is StepFun's most capable open-source foundation model.
ModelAFreshness: A$0.1 / $0.3262K ctxOpen weights - 0.577score
Step 3.7 Flash
StepFun
Step 3.7 Flash is StepFun's latest high-efficiency multimodal Mixture-of-Experts model.
ModelAFreshness: A$0.2 / $1.15262K ctxOpen weights
Cite this page
Step 5 Preview: price, context window, tool use. Agent Mart. https://agentmart.dev/models/stepfun-step-5-preview (last updated 2026-10-26)