Step 5 Preview API
StepFun's chat model. Call it on 666 AI with the same API key as every other model. Pay as you go; prices follow the upstream in real time and this page updates hourly.
| Vendor | StepFun |
| Type | chat |
| Price | $1.35 per 1M input tokens · $3.65 per 1M output tokens |
| Live test | Passed our live test in the last 7 days |
| Latency (short request) | Median ~1s (5+ calls in the last 7 days) |
| Model ID (use this in your request) | stepfun/step-5-preview |
How to call Step 5 Preview
The API is OpenAI-compatible. Replace YOUR-ENDPOINT with the endpoint shown on your API Key page after you sign up, and YOUR-KEY with your key.
curl https://YOUR-ENDPOINT/v1/chat/completions \
-H "Authorization: Bearer YOUR-KEY" \
-H "Content-Type: application/json" \
-d '{"model": "stepfun/step-5-preview", "messages": [{"role": "user", "content": "Hello"}]}'from openai import OpenAI
client = OpenAI(base_url="https://YOUR-ENDPOINT/v1", api_key="YOUR-KEY")
r = client.chat.completions.create(
model="stepfun/step-5-preview",
messages=[{"role": "user", "content": "Hello"}],
)
print(r.choices[0].message.content)Similar models — price comparison
| Model | Price |
|---|---|
| Kimi K2.5 | $0.7695 per 1M input tokens · $3.85 per 1M output tokens |
| Dola Seed 2.0 Pro | $0.675 per 1M input tokens · $4.05 per 1M output tokens |
| Seed 2.0 Pro | $0.675 per 1M input tokens · $4.05 per 1M output tokens |
| Gemini 3.6 Flash | $0.9113 per 1M input tokens · $4.56 per 1M output tokens |
| Gemini 3.7 Flash | $0.9113 per 1M input tokens · $4.56 per 1M output tokens |
| Gemini 3.8 Flash | $0.9113 per 1M input tokens · $4.56 per 1M output tokens |
FAQ
How much does the Step 5 Preview API cost?
On 666 AI, Step 5 Preview costs $1.35 per 1M input tokens · $3.65 per 1M output tokens. You pay only for what you use — no monthly fee. Prices follow the upstream in real time; this page updates every hour.
Can I use the official OpenAI SDK?
Yes. The API is OpenAI-compatible: in the OpenAI Python or Node.js SDK just change base_url and api_key, and set model to stepfun/step-5-preview.
How do I pay?
Bank card (including Google Pay / Apple Pay), USDT / ETH, or bank wire. Top up once and usage is deducted as you go.