One agent session
1M input tokens and 100K output tokens, no caching.
- Input1M x $1 = $1.00
- Output0.1M x $2.70 = $0.27
$1.27per session
StepFun - Open weights
Step 5 Preview pricing and specs
Step 5 Preview is an open-weights model from StepFun that costs $1 per 1M input tokens and $2.70 per 1M output tokens on the first-party API, with a 1M-token context window.
Last verified from platform.stepfun.ai. All sources
- Input / 1M
- $1
- Output / 1M
- $2.70
- Context
- 1M tokens
- Weights
- Open
Pricing per 1M tokens
| Item | Price / 1M tokens |
|---|---|
| Input | $1 |
| Output | $2.70 |
| Cache read | $0.10 |
Note: StepFun international platform, priced in USD. Cache-miss input price includes writing new content to the cache, so no separate cache write price is billed. Output tokens include reasoning and final answer. Model docs state a 1M-token context window and 64k maximum output (recorded as 1,000,000 and 64,000). Text, image and video input; text output. The release date is left blank because the launch post (stepfun.com/step-5-preview) carries no date; it says open weights would follow on October 15. No batch pricing published.
Specs
- Context window
- 1,000,000 tokens
- Max output
- 64,000 tokens
- Provider
- StepFun
- API model id
step-5-preview- Vercel AI Gateway id
stepfun/step-5-preview- Weights
- Open weights
- License
- StepFun Model License 1.0 (Hugging Face license tag: other)
- Weights download
- huggingface.co
What Step 5 Preview costs in practice
Worked from the standard list rates above, with the math shown so you can swap in your own token counts.
A chat app
10,000 requests a day at 2K input and 500 output tokens each.
- Input20M x $1 = $20.00
- Output5M x $2.70 = $13.50
$33.50per day
$1,005.00 per 30-day month
The same session at a 90% cache hit
90% of the input is read from the prompt cache. The one-time cache write premium is not included.
- Cached input0.9M x $0.10 = $0.09
- Uncached input0.1M x $1 = $0.10
- Output0.1M x $2.70 = $0.27
$0.46per session
Compare with
| Model | Input / 1M | Output / 1M |
|---|---|---|
| Step 5 Preview (this page) | $1 | $2.70 |
| ERNIE 5.1Baidu | $0.56 | $2.53 |
| Hy4 previewTencent | $0.834 | $2.501 |
| Amazon Nova 2 LiteAmazon | $0.30 | $2.50 |
| Dola Seed 2.1 TurboByteDance Seed | $0.50 | $2.50 |
| Step 3.7 FlashStepFun | $0.20 | $1.15 |
| Step-1o Turbo VisionStepFun | $0.36 | $1.15 |
| Step 3.5 FlashStepFun | $0.10 | $0.30 |
| Step 3.5 Flash 2603StepFun | $0.10 | $0.30 |
Related reading
- Step 5 Preview: Pricing, Benchmarks and the October 15 Open WeightsStep 5 Preview is StepFun's 600B MoE with 27B active and a 1M window. What it scores, what a session costs, and what to check before the October 15 weights.
- Build Your First Agent with Vercel eve: A Step-by-Step TutorialBuild your first AI agent with Vercel eve: scaffold a project, add a typed tool with defineTool, run it locally, call the session API and deploy to Vercel.
- Agent Architecture: Building Multi-Step AI Workflows That Survive ProductionAgent architecture for multi-step Claude workflows: loop patterns, state management, error recovery, and the production gotchas that break agents at scale.
- The Agent Reliability Cliff: Why Your 10-Step Chain Only Succeeds 20% of the TimeThe agent reliability cliff: 85% per-step success compounds to about 20% over 10 steps. Why long chains collapse, and six patterns that fight the decay.
FAQ
How much does Step 5 Preview cost per million tokens?
Step 5 Preview costs $1 per 1M input tokens and $2.70 per 1M output tokens on StepFun's first-party API, per platform.stepfun.ai on October 17, 2026. Per 1M tokens, cache reads cost $0.10.
What is Step 5 Preview's context window?
Step 5 Preview has a 1,000,000-token context window and returns up to 64,000 output tokens per response.
Are Step 5 Preview's weights open?
Yes. Step 5 Preview's weights are published at https://huggingface.co/stepfun-ai/Step-5-Preview under the StepFun Model License 1.0 (Hugging Face license tag: other).
Sources
Last verified from platform.stepfun.ai.
- https://platform.stepfun.ai/docs/en/guides/pricing/details
- https://platform.stepfun.ai/docs/en/guides/models/step-5-preview
- https://platform.stepfun.ai/docs/en/guides/models/overview
- https://www.stepfun.com/step-5-preview
- https://huggingface.co/stepfun-ai/Step-5-Preview
- https://huggingface.co/stepfun-ai/Step-5-Preview/blob/main/LICENSE.txt
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