Major Release StepFun · Released
Step 3.5 Flash
What is Step 3.5 Flash?
Step 3.5 Flash is a Major Release AI model from StepFun, released on February 2, 2026. It has a 256K tokens context window, costs $0.10 per million input tokens, and scores 1393 on Chatbot Arena Elo. It is available as open source.
StepFun Step 3.5 Flash — AA Intelligence Index 37.8, 256K tokens context, reasoning model.
How much does Step 3.5 Flash cost?
| Metric | Price |
|---|---|
| input per mtok | $0.10 |
| output per mtok | $0.30 |
Pricing data verified .
What context window does Step 3.5 Flash have?
- Context window
- 256K tokens
- Max output
- 250K
- Input modalities
- text
- Output modalities
- text
How does Step 3.5 Flash score on benchmarks?
| Benchmark | Score |
|---|---|
| GPQA Diamond | 83.1% |
| HLE | 19.1% |
| SciCode | 40.4% |
| TAU2-bench | 94.4% |
| TerminalBench-Hard | 27.3% |
| IF-Bench | 64.6% |
| LiveCodeBench Reasoning | 43.0% |
| AA Intelligence Index | 37.8 |
| Chatbot Arena Elo | 1393 |
Benchmark scores verified .