Step 3.5 Flash
stepfun/step-3.5-flash- StepFun
- Family · Step 3 Flash
- Released 2 Feb 2026
- Open weights
- Text → Text
- Tools
Not on OSMEXO yet
Spec & list price
Context256K
Max output64K
Input / 1M$0.10
Output / 1M$0.303× input
Scores · standing
Intelligence17.0#159/490
Usage
Tokens / day202.0M▼ 1.8% 7d
Usage rank#269
Requests / day29.0K
Tool calls / req0.18
Per request · 30 days
Avg input10.8K0.7× median
Avg output1.8K2.6× median
Reasoning share88%1.6× median
Tool-call failures3.3%1.8× median
Consumption
Peak 564.2M 2 OctLow 147.0M 10 OctRank today #269
Benchmarks
bar = share of the top score · Benchmark data: Artificial AnalysisSpeed · median across providers, latest day
Output speed#216/33452 tok/s1.3× slower than median
First token#1490.94 sabout median
#2 cheapest of 17 with a similar score
Value
Intelligence Index
Blended price per 1M tokens (log)
Family progress
Intelligence Index
- Family releases19.5
Technical details
- Tokenizer
- Other
- License
- Apache 2.0
- Parameters
- 199B
- Moderation
- none
- Downloads · likes
- 226.4K · 847
Request parameters 9
- tools
- tool_choice
- reasoning
- include_reasoning
- temperature
- top_p
- top_k
- max_tokens
- frequency_penalty
When to use
Best for
- Tool-using agents with strong benchmark results
- Science and reasoning Q&A on open weights
- Instruction-following pipelines
- Long-context reasoning at low cost
Think twice for
- Image understanding (text-only input)
- Strict structured output
- Image generation
Same family
Step 3 Flash- S19.5
Alternatives
other vendors · similar capability- 12.9
- 18.2
- 20.6
- 15.6
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