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Step 5 Preview

Ready
model path:accounts/fireworks/models/step-5-preview-fp8

Step 5 Preview is an open-weight model from StepFun for coding, software engineering, and agentic workloads. It uses a sparse Mixture-of-Experts architecture with 600B total / 27B active parameters across 92 layers, with Sparse GQA attention for long context. Context length: 128K tokens. Input: text. Output: text.

Step 5 Preview API Features

On-demand Deployment

Docs

On-demand deployments allow you to use Step 5 Preview on dedicated GPUs with Fireworks' high-performance serving stack with high reliability and no rate limits.

Metadata

State
Ready
Created on
8 OCT, 2026
Kind
Base model
Provider
StepFun

Specifications

Calibrated
No
Mixture-of-Experts
No
Parameters
604B

Supporting Functionality

Fine-tuning
Not Supported
Serverless
Not Supported
Context Length
1040k tokens
Function Calling
Not Supported
Embeddings
Not Supported
Rerankers
Not Supported
Supporting image input
Not Supported