StepFun model product
Step 3.5 Flash
5-Flash is StepFun's fast, cost-effective text model optimized for quick inference.
Updated Aug 17, 2026. Default version: Step-3.5-Flash
LLMBoard Score60.3Step-3.5-Flash
Coverage40%7 benchmark families
Context window256KTokens
Official input price$0.10StepFun (Global) API
Step 3.5 Flash Capability Profile
This profile uses the model's current scored version. Arena ratings and prices are shown separately.
Step 3.5 Flash Benchmark Results
Benchmark scores for Step-3.5-Flash.
Sort by
Benchmark | Score | Rank | Participants | Percentile | Evidence | Evaluated |
|---|
| BenchmarkTau-bench | Score88.2% | Rank01 | Participants6 | Percentile100.0% | EvidenceC | Evaluated |
| BenchmarkIMO-AnswerBench | Score85.4% | Rank09 | Participants20 | Percentile57.9% | EvidenceC | Evaluated |
| BenchmarkLiveCodeBench v6 | Score86.4% | Rank10 | Participants56 | Percentile83.6% | EvidenceC | Evaluated |
| BenchmarkAIME 2025 | Score97.3% | Rank14 | Participants115 | Percentile88.6% | EvidenceC | Evaluated |
| BenchmarkBrowseComp | Score69.0% | Rank31 | Participants62 | Percentile50.8% | EvidenceC | Evaluated |
| BenchmarkTerminal-Bench 2.0 | Score51.0% | Rank35 | Participants51 | Percentile32.0% | EvidenceC | Evaluated |
| BenchmarkSWE-Bench Verified | Score74.4% | Rank41 | Participants111 | Percentile63.6% | EvidenceC | Evaluated |
Step 3.5 Flash Arena Results
Preference and agent-evaluation results for the default version.
Sort by
Arena | Category | Rank | Rating / score | Votes | Observations | Result date |
|---|
| Arenatext factuality | Categoryoverall | Rank114 | Rating / score1417.5 | Votes57,159 | ObservationsN/A | Result date |
| Arenatext | Categoryoverall | Rank129 | Rating / score1403.7 | Votes57,522 | ObservationsN/A | Result date |
| Arenatext style control | Categoryoverall | Rank147 | Rating / score1394.5 | Votes57,522 | ObservationsN/A | Result date |
Step 3.5 Flash Pricing
Official vendor API pricing appears first, followed by individual provider offers.
- Official API
- $0.10 input, $0.30 output per 1M
- Official provider
- StepFun (Global)
- Lowest third-party
- From $0.09 input, $0.30 output per 1M via Vercel AI Gateway
- Tracked offerings
- 14
Sort by
Provider | Provider model ID | Region | Input / 1M | Output / 1M | Context | Updated |
|---|
| ProviderNvidia | Provider model IDstepfun-ai/step-3.5-flash | Regionglobal | Input / 1MN/A | Output / 1MN/A | Context256K | Updated |
| ProviderVercel AI Gateway | Provider model IDstepfun/step-3.5-flash | Regionglobal | Input / 1M$0.09 | Output / 1M$0.30 | Context262.1K | Updated |
| ProviderEden AI | Provider model IDdeepinfra/stepfun-ai/Step-3.5-Flash | Regionglobal | Input / 1M$0.09 | Output / 1M$0.30 | Context262.1K | Updated |
| ProviderNanoGPT | Provider model IDstepfun-ai/step-3.5-flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context256K | Updated |
| ProviderHugging Face | Provider model IDstepfun-ai/Step-3.5-Flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context262.1K | Updated |
| ProviderOpenRouter | Provider model IDstepfun/step-3.5-flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context262.1K | Updated |
| ProviderStepFun (Global) | Provider model IDstep-3.5-flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context256K | Updated |
| ProviderStepFun (China) | Provider model IDstep-3.5-flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context256K | Updated |
| ProviderZenMux | Provider model IDstepfun/step-3.5-flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context256K | Updated |
| ProviderEmpirioLabs AI | Provider model IDstep-3-5-flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context256K | Updated |
| ProviderKilo Gateway | Provider model IDstepfun/step-3.5-flash | Regionglobal | Input / 1M$0.10 | Output / 1M$0.30 | Context262.1K | Updated |
Official prices use only the vendor's configured official Provider and positive standard USD PAYG rates. Third-party offers remain explicitly labeled.
Step 3.5 Flash Runtime Performance
Provider-specific output speed and catalog latency for Step-3.5-Flash. Runtime does not affect the capability score.
Sort by
Provider | Output Speed | Catalog Latency | Max Input | Max Output | Updated |
|---|
| ProviderStepFun | Output Speed711.842 tok/s | Catalog Latency1.084 s | Max Input65.5K | Max Output8.2K | Updated |
Output Speed is generated output tokens received per second. Catalog latency is reported separately from observed provider TTFT.
Step 3.5 Flash Specifications
Technical details for the model's default version.
- Version
- Step-3.5-Flash
- Released
- Feb 2, 2026
- Knowledge cutoff
- Jan 1, 2025
- Parameters
- 196B
- Context window
- 256K
- Max output
- 256K
- Inputs
- image, text
- Outputs
- text
- Open weights
- Yes
- License
- Apache 2.0
Step 3.5 Flash Versions
Available versions of this model. The score column identifies the version used in the overall ranking.
Sort by
Version | Released | LLMBoard | Parameters | Context | Max output | Open weights | License |
|---|
| VersionStep-3.5-Flash | Released | LLMBoard60.3 | Parameters196B | Context256K | Max output256K | Open weightsYes | LicenseApache 2.0 |
Step 3.5 Flash vs nearby models
Open a comparison with the three ranked models immediately above and below this model.
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What is Step 3.5 Flash?
Key information about Step 3.5 Flash and its available data.
5-Flash is StepFun's fast, cost-effective text model optimized for quick inference. Built on their Step3 architecture, it offers strong performance across text tasks with low latency and efficient token usage, ideal for production workloads requiring speed and cost efficiency.
Data as of 2026-08-17.
FAQ
Common questions about Step 3.5 Flash.
When was Step 3.5 Flash released?
Step 3.5 Flash's default version was released on Feb 2, 2026.
How much does Step 3.5 Flash cost?
Step 3.5 Flash's official API price is $0.10 per million input tokens and $0.30 per million output tokens via StepFun (Global). The lowest tracked third-party offer starts at $0.09 input and $0.30 output via Vercel AI Gateway.
Who created Step 3.5 Flash?
Step 3.5 Flash was created by StepFun.
What is the context window for Step 3.5 Flash?
The default version has a 256K token context window.
Is Step 3.5 Flash open weight?
Yes. The default version is marked as open weight under Apache 2.0.
How many API providers offer Step 3.5 Flash?
14 provider offerings are linked to the default version.
What models should I compare Step 3.5 Flash with?
Nearby ranked alternatives include MiMo, GPT-5.1-Instant, Kimi K2 Thinking.