Sonar Reasoning Pro vs Step 3.5 Flash 2603
Perplexity vs StepFun — benchmarks, pricing, and capabilities side by side.
- •Sonar Reasoning Pro has the higher intelligence index (95.7 vs 82.6)
- •Step 3.5 Flash 2603 is cheaper ($0.00 vs $2.00 per 1M input)
| Sonar Reasoning Pro | Step 3.5 Flash 2603 | |
|---|---|---|
| Intelligence index | 95.7 | 82.6 |
| Developer | Perplexity | StepFun |
| Type | Multimodal | LLM |
| Access | API only | — |
| Context window | 128,000 tokens | — |
| Input price | $2.00 / 1M | $0.00 / 1M |
| Output price | $8.00 / 1M | $0.00 / 1M |
| Speed | — | 197 tok/s |
| Released | March 7, 2025 | April 2, 2026 |
| Parameters | — | — |
| Input modalities | Text, Image | — |
| Output modalities | Text | — |