# StepFun: step-5-preview — API on ChinaAPI

> StepFun Step 5 Preview — 600B-parameter sparse MoE flagship with 27B active parameters per token, 1M context, up to 64K output, native text/image/video understanding, always-on reasoning with low/medium/high effort, tool calling, structured output, streaming, and prompt caching.

- Canonical page: https://chinaapi.ai/models/step-5-preview/
- Model ID: `step-5-preview`
- Context window: 1M
- Modalities: Text, image and video input
- Pricing: $1/M input, $2.7/M output tokens (USD)
- Endpoint: OpenAI-compatible `POST https://api.chinaapi.ai/v1/chat/completions`
- Price note: Prompt cache reads are billed at $0.05 per 1M tokens. The standard input and output rates above are the live gateway book prices.
- Pricing basis: Standard model rates follow providers' international list prices at 100%; some models have a separate Paid rate after the first top-up.
- Live pricing: https://dash.chinaapi.ai/models/step-5-preview?lang=en&utm_source=chinaapi&utm_medium=model-md&utm_campaign=step-5-preview
- Access: no mainland-China account or phone number required; $2 free trial credit
- Sign up: https://dash.chinaapi.ai/register?lang=en&utm_source=chinaapi&utm_medium=model-md&utm_campaign=step-5-preview

## Quickstart

```
curl -X POST https://api.chinaapi.ai/v1/chat/completions \
  -H "Authorization: Bearer $CHINAAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "step-5-preview",
    "messages": [
      {"role": "user", "content": "Summarize the main tradeoffs for this API workload."}
    ]
  }'

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["CHINAAPI_API_KEY"],
    base_url="https://api.chinaapi.ai/v1",
)

response = client.chat.completions.create(
    model="step-5-preview",
    messages=[
        {"role": "user", "content": "Summarize the main tradeoffs for this API workload."}
    ],
)
print(response.choices[0].message.content)
```

## FAQ

**How do I use step-5-preview?**
Use step-5-preview through ChinaAPI with an API key and the OpenAI-compatible endpoint shown on this page.

**How much does step-5-preview cost?**
step-5-preview is $1/M input, $2.7/M output tokens, paid in USD. The live pricing page is authoritative. Standard model rates follow providers' international list prices at 100%; some models have a separate Paid rate after the first top-up.

**Does step-5-preview need a Chinese account?**
No. ChinaAPI provides access without a mainland-China account or phone number and includes a $2 free trial. Check live pricing for the displayed USD rate.

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Markdown twin of https://chinaapi.ai/models/step-5-preview/ — generated by scripts/gen_model_pages.py. Full catalog: https://chinaapi.ai/llms-full.txt