step-3.5-flash
Model overview
step-3.5-flash-2603
StepFun step-3.5-flash reasoning model.
general LLMreasoninglong contextchatsoftware engineering agententerprise access
Representative version
step-3.5-flash-2603
| Company | StepFun |
|---|---|
| Release | 2026-03-01 |
| Release type | Model release |
| Parameters | Not disclosed |
| Architecture | Not disclosed |
| Context | 262,144 |
| Input modalities | text / image / video |
| Output modalities | text / code / tool_call |
| Tool use / function calling | Confirmed: Tool use, Function calling |
| Structured output / reasoning | Confirmed: Reasoning |
| Vision / audio / video | Confirmed: Vision, Video |
| Open weights / License | No open weights / license not applicable stepfun-step-3-5-flash-2603 · License not applicable |
| Vendor API | Available StepFun API pricing and supported modelsstepfun-step-3-5-flash-2603 · 2026-03-01 |
| OpenRouter | OpenRouter listed |
| Pricing | OpenRouter · 2026-07-15 · step-3.5-flash: $0.1 / $0.3 input / output, per 1M tokens |
| Benchmark | LMArena 2 rows |
| Public signals | 1 runtime / access record / 1 activity snapshot |
| Use cases | Multimodal assistants / coding and review / Agent workflows / assistant chat |
| Claim evidence | Release eventStepFun API pricing and supported modelsstep-3.5-flash-2603 · 2026-03-01 Model specs / weightsStepFun model capability overviewstep-3.5-flash · step-3.5-flash-2603 |
OpenRouter
Pricing / context / availability
| OpenRouter | OpenRouter listed |
|---|---|
| OpenRouter listing | stepfun/step-3.5-flash |
| Mapped version | step-3.5-flash stepfun-step-3-5-flash-phase-3-5 |
| Pricing | OpenRouter · 2026-07-15 · step-3.5-flash: $0.1 / $0.3 input / output, per 1M tokens |
| Context | 262144 |
| Speed/Latency | No reliable public source |
| Snapshot time | 2026-07-15T20:11:41.551Z |
| Source | View source |
Benchmark
Ranking evidence
| Source | Task | Rank | Score | Sample | Time | Link |
|---|---|---|---|---|---|---|
| LMArena | Coding | 102 | 1,448.09 | 5,677 | 2026-05-07 | View source |
| LMArena | Text overall | 119 | 1,393.27 | 25,112 | 2026-05-07 | View source |
Public activity counters
Cumulative Hugging Face model-card downloads / likes / spaces
| Platform | Entry | Downloads | Likes | Spaces | Time | Source |
|---|---|---|---|---|---|---|
| huggingface | stepfun-ai/Step-3.5-Flash | 144,100 | 827 | 80 | 2026-07-15T20:11:41.551Z | View source |
Operations
Runtime / access signals
| Time | Signal | Original text | Source |
|---|---|---|---|
| 05/26/2026, 01:36 PM UTC | Questions re: config.json | Was running modelingstep3p5.py via huggingface, and I kept running into the error: In SafeTensors there seem to be 48 layers. I fixed this by... | Source |
Vertical comparison
Current available versions
| Version | Release | Parameters | Context | Input | Output | Open weights / License | Vendor API | Source tier |
|---|---|---|---|---|---|---|---|---|
| step-3.5-flash-2603 | 2026-03-01 | Not disclosed | 262,144 | text / image / video | text / code / tool_call | No open weights / license not applicable | Available | P0 |
| step-3.5-flash | Not disclosed | 196.81B / 11B active | 256,000 | text / code | text / code | Weight status not disclosed / license not disclosed | Available | P0 |
Evidence gaps
Public display boundary
Parameter scale not disclosedNo linkable real reviewSpeed/latency not disclosed