Step 3.5 Flash: API pricing, providers and specs
Step 3.5 Flash is a text model by StepFun. 8 providers serve it, from $0.292 to $0.33 /1M; the lowest price is at SiliconFlow.
A newer version is out: Step 3.7 Flash · released May 23, 2026
How Step 3.5 Flash compares
Against the 737 text models on the site priced the same way.
- Cheap for its class: at $0.292 /1M, its lowest price undercuts 77% of comparable models (median $1.10).
- Its 256K-token context window is larger than 38% of them (median 262K), about 380 pages of text.
- 8 providers serve it; 73% of comparable models have fewer.
- Its weights are open under the Apache 2.0 license: commercial use allowed.
Step 3.5 Flash prices by provider
Every provider's list price, read from its own price page or API. A price marked “from” changes with context length, resolution or mode.
| Provider | Input | Output | Prompt caching | Context |
|---|---|---|---|---|
 SiliconFlow | $0.097/1M | $0.292/1M | — | — |
| ZenMux | $0.10/1M | $0.30/1M | — | 256K |
 Hugging Face | $0.10/1M | From$0.30/1M | — | — |
| SiliconFlow | $0.10/1M | $0.30/1M | — | — |
 EmpirioLabs AI | $0.10/1M | $0.30/1M | $0.02/1M | 256K |
| OpenRouter | $0.10/1M | From$0.30/1M | — | 262K |
 LaoZhang API | $0.10/1M | $0.30/1M | — | — |
 AIHubMix | $0.11/1M | $0.33/1M | — | 256K |
- SiliconFlow$0.292
- ZenMux$0.30
- SiliconFlow$0.30
- EmpirioLabs AI$0.30
- LaoZhang API$0.30
- Hugging FaceFrom$0.30
- OpenRouterFrom$0.30
- AIHubMix$0.33
Specs
- Type
- Text
- Maker
- StepFun
- Inputs
- Text
- Outputs
- Text
- Context
- 256K≈ 380 pages of text
- Max output
- 66K
- Capabilities
- Reasoning, Tool calling
- Released
- Feb 1, 2026
- License
- Apache 2.0commercial use allowed
- Open weights
- Yes, downloadable
- Parameters
- 199B
Alternatives to Step 3.5 Flash
Same kind of model from other makers, at a similar price.
| Model | Lowest price | Context | Arena | Providers |
|---|---|---|---|---|
| Step 3.5 Flashthis model | $0.292/1M | 256K | — | 8 |
 GLM-5.3-Flash | $0.20/1M | 1.05M | 1608 | 45 |
 Qwen3.8 27B | $0.50/1M | 262K | 1591 | 33 |
| GPT-6 Luna | $0.40/1M | 1.05M | 1578 | 28 |
| Claude Haiku 5.5 | $0.30/1M | 1M | 1585 | 27 |
 MiMo-V2.6-Pro | $0.696/1M | 1.05M | 1625 | 21 |
| Qwen3.8 Flash Next | $0.376/1M | 262K | 1628 | 5 |
 DeepSeek V4 Flash | $0.17/1M | 1.05M | — | 26 |
| DeepSeek V4 Flash Vision Exp | $0.294/1M | 1.05M | — | 26 |
More from StepFun
GOT-OCR 2.0StepFun$0.05/imgStep 2 16KStepFun$2/1MStep 3.5 Flash 2603StepFun$0.30/1MStep 3.7 FlashStepFun$0.925/1MStep 5 PreviewStepFun$2.70/1MStep3StepFun$2.75/1MStepaudio 2.5StepFun$3.50/1MStepaudio 2.5 RealtimeStepFun$10/1MStep 3.5 Flash FAQ
The lowest price for Step 3.5 Flash is $0.292 /1M, at SiliconFlow.
SiliconFlow, at $0.292 /1M. 8 providers serve Step 3.5 Flash; the table above lists every one with its price.
Step 3.5 Flash reads up to 256K tokens per request and writes up to 66K.
Yes. Step 3.5 Flash's weights can be downloaded from its maker's Hugging Face page, under the Apache 2.0 license.
About 199B, as the safetensors metadata of its official Hugging Face repo states.
8 API providers serve Step 3.5 Flash. Compare their prices above, or open a provider to see everything it offers.
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