⚡️ Step 3.5 Flash is coming: Fast Enough to Think. Reliable Enough to Act！

We’re dropping our most capable open-source foundation model yet. Frontier reasoning meets extreme efficiency.

It leverages a sparse Mixture of Experts (MoE) architecture, 196B total → 11B active.

Key Capabilities:
✅Reasoning at Speed: MTP-3 powered throughput at 100–300 tok/s (350 tok/s peak for single-stream coding tasks).
✅Agentic Power: ⚡️ 74.4% SWE-bench Verified ⚡️ 51.0% Terminal-Bench 2.0. Proven stability for complex, long-horizon tasks.
✅256K Efficient Context: 3:1 SWA ratio + Full Attention. Massive datasets or long codebases support with minimal overhead. Consistent performance, hybrid efficiency.
✅Local-First Deployment: Optimized for Mac Studio M4 Max, NVIDIA DGX Spark. Secure, private, and frontier-capable. Your data, your hardware, your agent.

You can try Step 3.5 Flash right now:
👉 OpenRouter: openrouter.ai/stepfun/step-3…
👉 GitHub: github.com/stepfun-ai/Ste…
👉 HuggingFace：huggingface.co/stepfun-ai/Ste…
👉 Blog：static.stepfun.com/blog/step-3.5-…
👉 ModelScope: modelscope.cn/models/stepfun…

🌌 The Next：Step 4 training is officially LIVE！
We're calling on the world's boldest builders to co-creat the Step 4 right now. Let's define the Agentic Era together!

Join our Discord：discord.gg/RcMJhNVAQc

Try Step 3.5 Flash on NV NIM👉

build.nvidia.com/stepfun-ai/ste…

huggingface🤗

mtp3_bf16: huggingface.co/stepfun-ai/Ste…
mtp3_fp8: huggingface.co/stepfun-ai/Ste…
int4: huggingface.co/stepfun-ai/Ste…