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Step 5 Preview now on RouterPlus at $0.90/$2.43 via RunInfra
StepFun's 600B open-weight flagship is one model ID away.
StepFun's Step 5 Preview joined the RouterPlus catalog on November 10, 2026, served by RunInfra. StepFun calls it its flagship model for agentic work, with a focus on software engineering, professional knowledge work and finance. StepFun launched it in October and published the open weights on Hugging Face.
What changed
- New RouterPlus model ID:
stepfun/step-5-preview. - RunInfra serves it at $0.90 input, $0.09 cached input and $2.43 output per million tokens.
- The catalog lists a 1,048,576-token context window and up to 32,768 output tokens on this route.
- StepFun describes it as a sparse mixture-of-experts model with 600B total and 27B active parameters.
- Weights are on Hugging Face at
stepfun-ai/Step-5-Preview.
Pricing on RouterPlus
RouterPlus catalog, November 10, 2026, per million tokens:
| Provider | Input | Cached input | Output |
|---|---|---|---|
| RunInfra | $0.90 | $0.09 | $2.43 |
What to do
Call it on the same endpoint as any other model:
curl https://api.routerplus.com/v1/chat/completions \
-H "Authorization: Bearer $ROUTERPLUS_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "stepfun/step-5-preview", "messages": [{"role": "user", "content": "Hello"}]}'See what else RunInfra serves on RouterPlus, or browse all models.