Claude Sonnet 4.6 vs Step 3.5 Flash
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for Claude Sonnet 4.6 and Step 3.5 Flash.
Claude Sonnet 4.6
Sonnet 4.6 is Anthropic's most capable Sonnet-class model yet, with frontier performance across coding, agents, and professional work. It excels at iterative development, complex codebase navigation, end-to-end project management with...
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....
Technical Specifications
| Specification | Claude Sonnet 4.6 | Step 3.5 Flash |
|---|---|---|
| Provider | Anthropic | StepFun |
| Context Window | 1,000,000 tokens | 262,144 tokens |
| Agent Suitability | 94/100 | N/A |
| Time to First Token (TTFT) | 350 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2026-02-17 | 2026-01-29 |
API Pricing Comparison
Input Price per Million Tokens
Claude Sonnet 4.6
$3.00
Step 3.5 Flash
$0.10
Output Price per Million Tokens
Claude Sonnet 4.6
$15.00
Step 3.5 Flash
$0.30
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
Claude Sonnet 4.6 Quirks & Gotchas
- ▸Best balance of speed and capability — default for most Claude integrations
- ▸Computer-use (beta) feature enables autonomous UI interaction
Step 3.5 Flash Quirks & Gotchas
No developer gotchas reported.