All comparisons
Grok 4 Fast Reasoning vs o3
Side-by-side comparison of specifications, capabilities, and pricing.
| Released | 2026-03-01 | 2025-03-31 |
| Context window | — | — |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Unknown |
| Knowledge cutoff | — | — |
Capabilities | ||
| Multimodal | ||
| Function calling | ||
| Tool use | ||
| JSON mode | ||
Availability | ||
| Providers | ||