StepFun: Step 3.5 Flash

STEPFUN Developer Architecture Profile

Intelligence (ELO)1433Chatbot Arena Verified

Max Context262,144Tokens

API Cost / 1M$0.40Blended Prompt + Completion

Model Capabilities

Drafting
Classification
Coding & Logic
Fictional

Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....

Granular Pricing Matrix

Input Tokens (Prompt)$0.10 / 1M

Output Tokens (Completion)$0.30 / 1M

Pricing data via OpenRouter. Sync: 4/30/2026

Evaluate Competitors

VS Engine MatchupStepFun: Step 3.5 Flash vs Google: Gemma 4 31B VS Engine MatchupStepFun: Step 3.5 Flash vs Arcee AI: Trinity Large Thinking VS Engine MatchupStepFun: Step 3.5 Flash vs MoonshotAI: Kimi K2.5 VS Engine MatchupStepFun: Step 3.5 Flash vs OpenAI: GPT Audio Mini VS Engine MatchupStepFun: Step 3.5 Flash vs Qwen: Qwen Plus 0728 VS Engine MatchupStepFun: Step 3.5 Flash vs Meta: Llama 3.3 70B Instruct