Step 5 Preview open weights were scheduled for Oct 15; the API is live at $1/$2.70 per 1M. Official HF status, pricing, and how to try it on StepFun today.

StepFun put Step 5 Preview on a hosted API on October 8, 2026 and told developers the BF16 open weights would follow on October 15. That date is today. Here is what we could verify on the morning of October 15, 2026 in Asia/Saigon: the API price, the official page wording and whether the official Hugging Face org actually shipped a Step-5 repo.

API pricing (verified Oct 15)

On OpenRouter, stepfun/step-5-preview lists $1.00 input / $2.70 output per 1M tokens, with cache reads at $0.05 per 1M. Context is 1,000,000 tokens; max completion on that listing is 64K. StepFun is the sole provider OpenRouter routes to for this model.

Step 5 Preview API pricing $1/$2.70 per 1M tokens on OpenRouter
OpenRouter list rates checked October 15, 2026.

Full plan tables and worked examples live on our Step 5 Preview tool page. For price context against other frontier models, see GPT-6 Astra vs Sol and Claude Sonnet 4.5.

Open weights: scheduled, not confirmed official

StepFun’s product page still said this morning: “The model will be released with open weights on October 15.” That is a schedule line, not a “weights are live” notice.

StepFun official Step 5 Preview page still listing October 15 open weights
Screenshot of stepfun.com/step-5-preview, morning of October 15, 2026 ICT.

We checked huggingface.co/stepfun-ai the same morning. There was no Step-5 repository under the official org. Third-party mirrors (for example SHSLab and various GGUF/FP8 forks) exist, but they are community uploads — not StepFun’s official BF16 release.

  • Use today: hosted API via StepFun products or OpenRouter.
  • Expect: StepFun still lists October 15 as the open-weights date.
  • Do not claim: that official StepFun weights already shipped, unless stepfun.com or stepfun-ai HF explicitly shows them.

What Step 5 Preview is

Step 5 Preview is a sparse MoE: 600B total parameters, 27B active per token, multimodal input and a 1M-token context. StepFun pitches it at software engineering, long agent loops and finance workflows. Treat StepFun’s own benchmark table as vendor data.

If you are tracking the broader open-weight race, our Qwen 4 release date post and best AI model guide cover how we compare launches without treating every vendor scoreboard as gospel.

What to do today

  • Builders who need the model now: call the API; $1/$2.70 is already a strong list price.
  • Teams waiting for local weights: watch stepfun-ai on Hugging Face and the official product page before downloading mirrors.
  • Readers comparing models: start with our Step 5 Preview tool page, then stack it against Claude and GPT-6 list rates.

Frequently asked questions

Are Step 5 Preview open weights live?

StepFun scheduled BF16 open weights for October 15. As of the morning of October 15, 2026 (ICT), the official product page still listed that date and the stepfun-ai Hugging Face org had no Step-5 repository. Third-party mirrors are not the official release.

How much does Step 5 Preview cost on the API?

On OpenRouter on October 15, 2026: $1.00 per 1M input tokens, $2.70 per 1M output tokens and $0.05 per 1M cache-read tokens. Context is 1M tokens.

What is Step 5 Preview?

StepFun’s flagship agentic model launched October 8, 2026: 600B MoE with 27B active, 1M context, text/image/video input. Hosted API is available now.

How do I try Step 5 Preview today?

Call stepfun/step-5-preview on OpenRouter, or use StepFun’s own products linked from the official page. For a full pricing page, see our Step 5 Preview tool review.

Should I download a community Step-5 mirror?

Not for production. Community Hugging Face copies are not StepFun’s official upload. Wait for a stepfun-ai repository or an explicit product-page confirmation.