S
Stepfun
Step 3.5 Flash
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. It is a reasoning model that is incredibly speed efficient even at long contexts.
- Input / 1M tokens
- $0.100
- Output / 1M tokens
- $0.300
- Context window
- 262K tokens
- Provider
- Stepfun
Performance
Median streaming throughput and first-token latency measured by Artificial Analysis.
- Output tokens / sec
- 182 t/s
- Time to first token
- 0.87s
Benchmarks
Intelligence, coding, and math indexes plus the underlying evaluation scores.
- Intelligence Index
- 39
- Coding Index
- 35
- Math Index
- —
- MMLU-Pro
- —
- GPQA
- 82.6%
- HLE
- 22.6%
- LiveCodeBench
- —
- SciCode
- 38.5%
- MATH-500
- —
- AIME
- —
Benchmarks via Artificial Analysis