StepFun Step 3.5 Flash Pricing
All plans and pricing as of 2026-04-17
Self-hosted (Apache 2.0)
- ✓Apache 2.0 license on Step 3 + Step3-VL-10B
- ✓Weights on Hugging Face (stepfun-ai/step3)
- ✓Agent-focused tuning -- tool use, planning, multi-step reasoning
API (StepFun / OpenRouter)
- ✓Available on OpenRouter and select hosted providers
- ✓StepFun direct API for enterprise customers
- ✓Pricing in line with other mid-tier Chinese open-weight models
Is StepFun Step 3.5 Flash Worth the Price?
Value Score: 9/10
Overall Score: 7.8/10 · 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.
StepFun Step 3.5 Flash (February 2026) is the notable Chinese open-weight release that doesn't come from the top-3 labs (DeepSeek, Alibaba/Qwen, Zhipu/GLM). The agent-focused tuning and MoE efficiency (196B total / 11B active beats DeepSeek V3.2 at 3x larger) give it a real niche for teams building tool-use agents on open weights. Western community adoption is still early but StepFun is growing OpenRouter presence and the Step 3.5 Flash release is a credible first step into broader ecosystem relevance. Worth adding to any Chinese-open-weight shortlist alongside DeepSeek and Qwen.
How StepFun Step 3.5 Flash Pricing Compares
| Tool | Free Tier | Starting Price | Value Score | Overall |
|---|---|---|---|---|
| StepFun Step 3.5 Flash(this tool) | Yes | $0 | 9/10 | 7.8 |
| Qwen (Alibaba) | Yes | $0 | 10/10 | 8.8 |
| MiniMax M2 / M2.5 | Yes | $0 | 9.5/10 | 8.4 |
| Gemma 4 (Google) | Yes | $0 | 10/10 | 8.3 |
| IBM Granite 4.0 | Yes | $0 | 9.5/10 | 8.2 |
| Kimi K2.5 (Moonshot) | Yes | $0 | 8.5/10 | 8.1 |