StepFun: Step 3.5 Flash
Analysis Summary
StepFun: Step 3.5 Flash sits in the Professional tier on our leaderboard, ranked #58 of 525 published models on overall intelligence. At $0.100 input and $0.300 output per 1M tokens, it is among the most expensive on the market. It offers a generous context window for extended reasoning and code review and supports tool use and function calling.
Editorial notes
StepFun's Step 3.5 Flash delivers impressive reasoning and agentic performance at just $0.10/1M input tokens, making it one of the best value-for-capability models in this tier. Tool use and function calling are supported, and instruction-following scores are strong — a compelling choice for cost-conscious businesses running high-volume workflows.
Assessed April 24, 2026
Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?
Performance Profile
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..
Capabilities
Performance Indices
Source: Artificial Analysis
Benchmark Scores
Intelligence
Technical
Content
Benchmark data from Artificial Analysis and Hugging Face
How does StepFun: Step 3.5 Flash stack up?
Compare side-by-side with other professional models.
Model Information
| OpenRouter ID |
stepfun/step-3.5-flash
|
| Provider | stepfun |
| Release Date | January 29, 2026 |
| Context Length | 262,144 tokens |
| Max Completion | 65,536 tokens |
| Status | Active |
Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $0.10 | $0.000100 |
| Output | $0.30 | $0.000300 |
Live Performance
Live endpoint metrics — refreshed every 30 minutes.
