Grok 4.1 Fast
retired Retired
Grok 4.1 Fast is a retired xAI LLM API model. and shut down on May 15, 2026. Migrate any code that still calls grok-4-1-fast-reasoning to xai/grok-4-3.
Recommended action: migrate to
xai/grok-4-3.
Lifecycle & specs
- Provider
- xAI
- API model ID
grok-4-1-fast-reasoning- Status
- retired
- Released
- Dec 11, 2025
- Deprecated
- Apr 30, 2026
- Retirement date
- May 15, 2026
- Replacement
xai/grok-4-3- Context window
- 2,000,000 tokens
Source: official xAI documentation ↗ · ✓ verified