Step 3.5 Flash
by StepFuntext->text1 endpoint
Neura Intelligence Index
72.8/ 100
Rank
#66—
Confidence
lowBenchmarks
3(8% coverage)
Overview
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....
Capabilities
Text generation
Tool use / Function calling
Extended reasoning
Long context
Top-P sampling
Modalities
Input
Text
Output
Text
Technical Specifications
Context Window
262.1K tokens
Max Output
65.5K tokens
Tokenizer
Other
Uptime (24h)
10000.0%
Parameters
196000000000B
License
apache_2_0Open Weights
Country
🇨🇳CN
Release Date
February 2, 20267mo
Supported Parameters
frequency_penaltyinclude_reasoningmax_tokensreasoningtemperaturetool_choicetoolstop_ktop_p
Benchmark Performance
coding
| Benchmark | Score | Source |
|---|---|---|
| SWE-bench Verified | 74.4 | verified |
math
| Benchmark | Score | Source |
|---|---|---|
| AIME 2025 | 97.3 | verified |
agent
| Benchmark | Score | Source |
|---|---|---|
| BrowseComp | 69 | verified |
Performance Over Time
Pricing
Per 1M tokens
Input$0.10
Output$0.30
Added
January 29, 2026
Last synced 9/19/2026