grok-4-fast-reasoning vs GPT-5.1
| xAI grok-4-fast-reasoning | OpenAI GPT-5.1 | |
|---|---|---|
| Vendor | xAI | OpenAI |
| Context window | 2,097,152 | 400,000 |
| Max output | 30,000 | 128,000 |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| File input | Yes | Yes |
| Input | text, image | text, image |
| Output | text | text |
| Released | 2025-08-27 | 2025-11-12 |