StepFun Step 3.5 Flash vs Devin
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
Devin
The most autonomous AI coding agent -- Devin 2.2 (Feb 24 2026) adds desktop/GUI testing (Figma, browser automation), Devin Review (pull-request analysis catching ~30% more issues), and ~3x faster startup (~15s vs ~45s). Now embedded in Windsurf 2.0
Powered by Cognition proprietary orchestration over Claude / GPT / Gemini + Devin's own tuned components
| Category | StepFun Step 3.5 Flash | Devin |
|---|---|---|
| Ease of Use | 6.0 | 6.5 |
| Output Quality | 8.0 | 8.0 |
| Value | 9.0 | 7.0 |
| Features | 8.0 | 8.0 |
| Overall | 7.8 | 7.4 |
Pricing Comparison
| Feature | StepFun Step 3.5 Flash | Devin |
|---|---|---|
| Free Tier | Yes | No |
| Starting Price | $0 | $20 |
Which Should You Pick?
Pick StepFun Step 3.5 Flash if...
- ✓Better value for money (9/10)
- ✓Has a free tier
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 Devin if...
Development teams that want to offload well-scoped tasks like bug fixes, test writing, and boilerplate code to an autonomous agent. Best when the task description is detailed and specific.
Visit DevinOur Verdict
StepFun Step 3.5 Flash edges out Devin with a 7.8 vs 7.4 overall score. Both are solid picks, but StepFun Step 3.5 Flash has the advantage in value.