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StepFun · Language model
Step 5 Preview
stepfun/step-5-preview- Language
Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters). It performs strongly in software engineering and professional...
Specifications
- Context window
- 1,000,000 tokens
- Max output
- 64,000 tokens
- Input
- text, image, video
- Output
- text
- Reasoning effort
- high, medium, low (always on)
- Tokenizer
- Other
Supported parameters
Accepted by the model and forwarded as-is by the gateway.
- frequency_penalty
- logprobs
- max_tokens
- reasoning
- reasoning_effort
- response_format
- stop
- structured_outputs
- temperature
- tools
- top_logprobs
- top_p
Use it
POST /api/v1/chat/completions · MCP chat · full reference
curl https://omnirail.org/api/v1/chat/completions \
-H "Authorization: Bearer $OMNIRAIL_KEY" -H "Content-Type: application/json" \
-d '{"model":"stepfun/step-5-preview","messages":[{"role":"user","content":"Hello"}],"max_tokens":300}'