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StepFun: stepfun/step-3.5-flash
stepfun/step-3.5-flash
262.1K context65.5K outReasoningTools
Released Jan 29, 2026Updated Nov 5, 2026
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....
Inputs used for the providers' own purposes
At least one provider of this model uses your inputs for its own purposes, for example to train AI models. Do not enter personal data of third parties or sensitive data. You can object to this use at any time in your account settings or via "Manage consents" in the chat.
Read the privacy policyPricing
Input price
$0.10/ 1M tokens
Output price
$0.30/ 1M tokens
Compatible endpoints openaiVendor StepFunProvider Routerah
Uptime
Performance
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Usage & Ranking
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Supported parameters
All providers = every upstream serving this model supports it. Some providers = depends on which upstream handles the request. Default = the value sent when you leave the parameter unset.
| Parameter | Providers | Default |
|---|---|---|
| frequency_penalty | Some providers | - |
| include_reasoning | Some providers | - |
| max_tokens | Some providers | - |
| reasoning | Some providers | - |
| temperature | Some providers | - |
| tool_choice | Some providers | - |
| tools | Some providers | - |
| top_k | Some providers | - |
| top_p | Some providers | - |