GPT-5.5 vs grok-4-fast-non-reasoning
| OpenAI GPT-5.5 | xAI grok-4-fast-non-reasoning | |
|---|---|---|
| Vendor | OpenAI | xAI |
| Context window | 1,050,000 | 2,097,152 |
| Max output | 128,000 | 30,000 |
| Reasoning | Yes | No |
| Tool calling | Yes | Yes |
| File input | Yes | Yes |
| Input | text, image | text, image |
| Output | text | text |
| Released | 2026-04-23 | 2025-08-27 |