Step 3.5 Flash: Pricing, Context Window & Benchmarks
by StepFun
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.
What you can do with Step 3.5 Flash
Everyday Q&A and clear explanations
Writing help (emails, posts, summaries)
Idea generation and brainstorming
Learning support with step-by-step guidance
Benchmarks not available
This model isn't listed on Artificial Analysis yet. Showing OpenRouter specs below.
| Metric | Value |
|---|---|
| Provider | StepFun |
| Context Window | 256,000 tokens |
| Input Price | $0.10/1M tokens |
| Output Price | $0.30/1M tokens |
| Release Date | Jan 29, 2026 |
| Modalities | text |
| Capabilities | N/A |
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Frequently asked questions
What is Step 3.5 Flash good for?
Use Step 3.5 Flash for everyday tasks like writing, summarizing, brainstorming, and getting clear explanations.
How much does Step 3.5 Flash cost?
Pricing is based on usage. Current rates are $0.10/1M tokens for input and $0.30/1M tokens for output.
Can I try Step 3.5 Flash for free?
Yes. You can start a chat instantly and test the model before deciding on a plan.
Does Step 3.5 Flash support images or audio?
Step 3.5 Flash focuses on text-based tasks.
Similar models
Pricing, context, and capability data are sourced from OpenRouter.
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