StepFun Step 3.5 Flash vs Grammarly
Which one should you pick? Here's the full breakdown.
StepFun Step 3.5 Flash
StepFun's (China) agent-focused open-weight model -- Step 3.5 Flash launched 2026-02-01. 196B sparse MoE, ~11B active. Benchmarks slightly ahead of DeepSeek V3.2 at over 3x smaller total size. Step 3 (321B / 38B active, Apache 2.0) and Step3-VL-10B multimodal also in the family
Grammarly
AI writing assistant that catches errors everywhere you type -- now with full AI rewriting
| Category | StepFun Step 3.5 Flash | Grammarly |
|---|---|---|
| Ease of Use | 6.0 | 10.0 |
| Output Quality | 8.0 | 7.0 |
| Value | 9.0 | 7.0 |
| Features | 8.0 | 8.0 |
| Overall | 7.8 | 8.0 |
Pricing Comparison
| Feature | StepFun Step 3.5 Flash | Grammarly |
|---|---|---|
| Free Tier | Yes | Yes |
| Starting Price | $0 | $0 |
Which Should You Pick?
Pick StepFun Step 3.5 Flash if...
- ✓Higher output quality (8 vs 7)
- ✓Better value for money (9/10)
Teams building agent systems on Chinese open-weight foundations who want something other than DeepSeek or Qwen, especially if agentic tool-use is the primary workload. Also good for Chinese-market products where StepFun's domestic tuning advantages matter. And for anyone looking to add diversity to their open-weight evaluation matrix beyond the top-3 Chinese labs.
Visit StepFun Step 3.5 FlashPick Grammarly if...
- ✓Easier to use (10 vs 6)
Non-native English speakers, professionals who write lots of emails, and anyone who wants a passive grammar net running in the background. It catches things you'd miss.
Visit GrammarlyOur Verdict
StepFun Step 3.5 Flash and Grammarly are extremely close overall. Your choice comes down to specific needs -- StepFun Step 3.5 Flash is better for teams building agent systems on chinese open-weight foundations who want something other than deepseek or qwen, especially if agentic tool-use is the primary workload, while Grammarly works best for non-native english speakers, professionals who write lots of emails, and anyone who wants a passive grammar net running in the background.