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

Stable Audio
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 |
| Free tier | Yes | Yes |
| Starting price | $0 | $0 |
| Best for | Teams building agent systems on Chinese open-weight foundations who want something other than DeepSeek or Q… | Developers and music/SFX creators who want a copyright-clean, license-backed AI audio model -- especially a… |
| Last reviewed | 2026-04-17 | 2026-05-26 |
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
Free tier available
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 FlashDevelopers and music/SFX creators who want a copyright-clean, license-backed AI audio model -- especially anyone who needs to self-host or fine-tune (Small/Medium open weights), or who is wary of the UMG/Sony litigation hanging over Suno and Udio.
Visit Stable AudioBottom line
StepFun Step 3.5 Flash edges out Stable Audio 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.
Pricing-wise, both tools have a free tier (StepFun Step 3.5 Flash starts $0, Stable Audio starts $0), so you can test either without committing. Compare what each free tier actually unlocks -- usage caps, model access, and feature gates differ a lot more than the headline price suggests, especially as both vendors have tightened limits in 2026.
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 Stable Audio when developers and music/sfx creators who want a copyright-clean, license-backed ai audio model -- especially anyone who needs to self-host or fine-tune (small/medium open weights), or who is wary of the umg/sony litigation hanging over suno and udio. 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 Stable Audio'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 Stable Audio 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 Stable Audio review
Tier B · 7.4/10
StepFun Step 3.5 Flash alternatives
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Stable Audio alternatives
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Built from our daily AI-tool sweep, last touched May 26, 2026. Honest tier-list reviews — no affiliate-link pieces disguised as advice. See the rubric or how we review.