Step 5 Preview
stepfun/step-5-previewStep 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture with 27B active and 600B total parameters. It accepts text, image, and video input with a 1M-token context window, and supports tool calling, structured outputs, and configurable reasoning.
- Input price
- $1.00USD / 1M tokens
- Output price
- $2.70USD / 1M tokens
- Context window
- 1M
- Max output
- 64K
Try the model
Playground
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Choose an example or write a prompt, then click Run.
Model card
Specifications
Pricing
- Input
- $1 / 1M tokens
- Output
- $2.70 / 1M tokens
- Cache read
- $0.05 / 1M tokens
Context & modalities
- Context window
- 1,000,000 tokens
- Max output
- 64,000 tokens
- Input
- Text, image
- Output
- Text
Capabilities
- Chat
- Supported
- Vision
- Supported
- Reasoning
- Supported
- Structured output
- Supported
- Function calling
- Supported
- Audio input
- Not supported
Access
- Provider
- Stepfun
- Model ID
- stepfun/step-5-preview
- Execution
- sync
- Base URL
- https://api.sandbase.ai
- API
- Chat Completions API
- Endpoint
- /v1/chat/completions
Start building
Send your first request
OpenAI-compatible endpoint with unified authentication and usage tracking.
# The quoted heredoc keeps Unicode and shell metacharacters unchanged.
result=$(curl --fail-with-body --silent \
-X POST "https://api.sandbase.ai/v1/chat/completions" \
-H "Authorization: Bearer $SANDBASE_API_KEY" \
-H "Content-Type: application/json" \
--data-binary @- <<'SANDBASE_JSON'
{
"model": "stepfun/step-5-preview",
"messages": [
{
"role": "user",
"content": "Hello"
}
],
"max_tokens": 2048
}
SANDBASE_JSON
)
printf '%s\n' "$result"Choose your model
Compare models
| Model | Context | Input / 1M | Output / 1M | Released |
|---|---|---|---|---|
Step 5 PreviewThis model Stepfun | 1M | $1.00 | $2.70 | Oct 8, 2026 |
Questions
FAQ
How do I call Stepfun Step 5 Preview through SandBase?
Create a SandBase API key, then send requests with the model ID "stepfun/step-5-preview" to Chat Completions API (/v1/chat/completions) at https://api.sandbase.ai. The request examples on this page show the exact payload.
How much does Stepfun Step 5 Preview cost?
$1 per 1M input tokens and $2.70 per 1M output tokens, billed per request from your SandBase balance. Discounts, when available, are shown in the pricing on this page.
What is the context window of Stepfun Step 5 Preview?
1M tokens of context, with up to 64K output tokens per response.
Which features does Stepfun Step 5 Preview support?
Stepfun Step 5 Preview supports vision (image input), reasoning, function calling, structured output. See Specifications above for the full list.
Do I need a separate Stepfun account?
No. One SandBase API key and balance gives you access to Stepfun Step 5 Preview and the other models in the catalog; you do not need to sign up with Stepfun separately.