Overview
StepFun’s multimodal reasoning foundation model, co-designed around MoE and MFA/AFD system components with 321B total and 38B active parameters.
Step 3
StepFun’s multimodal reasoning foundation model, co-designed around MoE and MFA/AFD system components with 321B total and 38B active parameters.
MODEL NUMBER337
- First public date
- 2025-07-31
- Organization
- StepFun
- Family
- Step
01
Specifications
Only published specifications are shown.
02
Overview
Why it mattered
Step 3 is a key point where StepFun’s public-weight path moved from early product models to efficient multimodal reasoning and model-system co-design.
PreviousStep-2— · — ctx
CurrentStep 3321B · 66K ctx
04
Architecture & capabilities
Model capabilities
ReasoningCodingTool use
05
Release history
Step 3 multimodal reasoning foundation model was open-sourced.
View source06
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07
Sources
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