GLM 5.1 vs gpt-5-pro
| Z.ai GLM 5.1 | OpenAI gpt-5-pro | |
|---|---|---|
| Vendor | Z.ai | OpenAI |
| Context window | 200,000 | 400,000 |
| Max output | 128,000 | 272,000 |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| File input | No | Yes |
| Input | text | text, image |
| Output | text | text |
| Released | 2026-04-07 | 2025-08-07 |