GLM / Z.ai (Zhipu AI) vs StepFun Step 3.5 Flash
Which one should you pick? Here's the full breakdown.
GLM / Z.ai (Zhipu AI)
Zhipu AI's open-weights family -- GLM-5.1 (launched 2026-04-07) is 744B MoE / 40B active, topped SWE-Bench Pro at 58.4 (beating GPT-5.4 and Claude Opus 4.6), MIT licensed, 200K context. Trained entirely on 100K Huawei Ascend 910B chips -- first frontier model with zero Nvidia in the training stack
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
| Category | GLM / Z.ai (Zhipu AI) | StepFun Step 3.5 Flash |
|---|---|---|
| Ease of Use | 6.5 | 6.0 |
| Output Quality | 8.5 | 8.0 |
| Value | 9.0 | 9.0 |
| Features | 8.0 | 8.0 |
| Overall | 8.0 | 7.8 |
Pricing Comparison
| Feature | GLM / Z.ai (Zhipu AI) | StepFun Step 3.5 Flash |
|---|---|---|
| Free Tier | Yes | Yes |
| Starting Price | $0 | $0 |
Benchmark Head-to-Head
GLM-5.1 (744B MoE / 40B active) benchmarks — StepFun Step 3.5 Flash has no published benchmarks
| Benchmark | Description | Score |
|---|---|---|
| SWE-Bench Pro | 58.4% | |
| MMLU-Pro | Harder multi-subject reasoning | 81.2% |
| GPQA Diamond | Graduate-level science questions | 74.5% |
| HumanEval | Python code generation | 89.1% |
| SWE-Bench Verified | 64.2% | |
| BFCL (function calling) | 88% |
Which Should You Pick?
Pick GLM / Z.ai (Zhipu AI) if...
Teams that need genuine MIT-licensed frontier open weights with no commercial strings. Especially strong for agentic workflows and vision (GLM-4.6V).
Visit GLM / Z.ai (Zhipu AI)Pick StepFun Step 3.5 Flash if...
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 FlashOur Verdict
GLM / Z.ai (Zhipu AI) and StepFun Step 3.5 Flash are extremely close overall. Your choice comes down to specific needs -- GLM / Z.ai (Zhipu AI) is better for teams that need genuine mit-licensed frontier open weights with no commercial strings, while StepFun Step 3.5 Flash works best for 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.