StepFun Step 3.5 Flash
Free tier available
- Self-hosted (Apache 2.0)$0
- API (StepFun / OpenRouter)Usage-based/per 1M tokens
Our pickStepFun Step 3.5 Flash

Devin
Cognition proprietary orchestration over Claude / GPT / Gemini + Devin's own tuned components
Tier-list head-to-head. StepFun Step 3.5 Flash takes the B-tier slot — here's the breakdown.
Spec sheet
| Tier | B-tierwin | B-tier |
| Overall score | 7.8 / 10win | 7.4 / 10 |
| Powered by | — | Cognition proprietary orchestration over Claude / GPT / Gemini + Devin's own tuned components |
| Free tier | Yeswin | No |
| Starting price | $0 | $20 |
| Best for | Teams building agent systems on Chinese open-weight foundations who want something other than DeepSeek or Q… | Development teams that want to offload well-scoped tasks like bug fixes, test writing, and boilerplate code… |
| Last reviewed | 2026-04-17 | 2026-05-21 |
Head-to-head
Rated 1-10 on the same rubric across all 130 tools we cover.
What you'll pay
Look past the headline number -- entry-tier limits drive most cost surprises.
Free tier available
No free tier
The decision
Use-case anchors and category strengths, side by side.
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 FlashDevelopment 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 DevinBottom line
StepFun Step 3.5 Flash edges out Devin by 0.4 points (7.8 vs 7.4) -- a B-tier vs B-tier split that's narrow but real. Not a blowout; both belong on a shortlist. The score gap shows up most clearly in the categories that matter for StepFun Step 3.5 Flash's strengths, so if those categories are your priority, the lead translates.
On pricing, StepFun Step 3.5 Flash starts free while Devin requires a paid plan from day one ($20+). If you're testing the waters or running an occasional workload, that gap matters more than the score differential. StepFun Step 3.5 Flash starts at $0; Devin starts at $20. Compare what each entry tier actually unlocks before you compare list prices -- the limits matter more than the headline number.
By use case: pick StepFun Step 3.5 Flash when 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. Pick Devin when development teams that want to offload well-scoped tasks like bug fixes, test writing, and boilerplate code to an autonomous agent. The two tools aren't fighting for the same person -- they're aiming at adjacent jobs that occasionally overlap. If you're squarely in StepFun Step 3.5 Flash's lane, the tier-list ranking and the use-case fit point the same direction; if you're in Devin's lane, the score gap matters less than the fit.
Bottom line: StepFun Step 3.5 Flash is the safer default for most readers, but Devin is competitive enough that the tie-breaker is your specific workload, not the spec sheet.
Keep digging
Full StepFun Step 3.5 Flash review
Tier B · 7.8/10
Full Devin review
Tier B · 7.4/10
StepFun Step 3.5 Flash alternatives
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Built from our daily AI-tool sweep, last touched May 21, 2026. Honest tier-list reviews — no affiliate-link pieces disguised as advice. See the rubric or how we review.