StepFun: Step 3.5 Flash
by StepFunStepFun: Step 3.5 Flash is a large language model from StepFun. It costs $0.100 per million input tokens and $0.300 per million output tokens. Its context window is 262K tokens.
ReasoningTool callingOpen weights
- Input / 1M tokens
- $0.100
- Output / 1M tokens
- $0.300
- Cached input / 1M
- -
- Context window
- 262K
Not supported
tokens
Who serves it cheapest
1 hosts serve Step 3.5 Flash. Same weights, same API - the price difference is pure margin and routing.
| Provider | Input / 1M | Output / 1M | Context | Throughput | Uptime 24h |
|---|---|---|---|---|---|
| SiliconFlowCheapestfp8 | $0.100 | $0.300 | 262K | - | 100.0% |
About 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....
Specifications
| Model ID | stepfun/step-3.5-flash |
|---|---|
| Provider | StepFun |
| Context window | 262K tokens |
| Max output | 66K tokens |
| Input modalities | text |
| Output modalities | text |
| Knowledge cutoff | - |
| Open weights | Yes - stepfun-ai/Step-3.5-Flash |
| Released | January 29, 2026 |
Cheaper alternatives
Models that cost less than Step 3.5 Flash while keeping at least half its context window and every input modality it supports.
Frequently asked
How much does StepFun: Step 3.5 Flash cost?
$0.100 per million input tokens and $0.300 per million output tokens.
What is the context window of StepFun: Step 3.5 Flash?
262K tokens, with up to 66K tokens of output per request.