The Orchestrator › Models › StepFun
StepFun: 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
| Provider | StepFun |
| Model ID | stepfun/step-3.5-flash |
| Context window | 262K tokens (262,144) |
| Modalities | text → text |
| Tokenizer | Other |
| Router sources | OpenRouter, TrustedRouter |
| Released | 2026-01-29 |
| Tracked since | 2026-11-14 |
| Popularity | Not in the ranked set |
| Reasoning | Mandatory |
Pricing (per million tokens)
| Variant | Source | API ID | Input | Output | Context |
|---|---|---|---|---|---|
| standard | OpenRouter | stepfun/step-3.5-flash | $0.1 | $0.3 | 262K |
| standard | TrustedRouter | stepfun/step-3.5-flash | $0.105 | $0.317 | 262K |
Recorded price history
| Date | Input / 1M | Output / 1M | Context |
|---|---|---|---|
| 2026-11-14 | $0.105 | $0.317 | 262K |
| 2026-11-14 | $0.1 | $0.3 | 262K |
Capabilities
Agentic tool useReasoning (always on)256K+ context windowControllable reasoningNo content storage (attested)
Trust flags come from TrustedRouter's per-provider attestations.
Supported parameters
frequency_penalty, include_reasoning, max_tokens, reasoning, temperature, tool_choice, tools, top_k, top_p