# grok-4-fast-reasoning

Since May 15, 2026, xAI answers calls to the model grok-4-fast-reasoning from a newer version.

- API: xAI (api.x.ai)
- Model: grok-4-fast-reasoning
- Kind: Model retirement
- Takes effect: May 15, 2026
- Calls after that day: answered by a newer version
- Calls it hits: `model grok-4-fast-reasoning`
- Source: [Model notices](https://docs.x.ai/llms.txt#model-retirement)
- Page: https://www.okapi.bot/models/xai/grok-4-fast-reasoning/

## What to use instead

Move to grok-4.3 with low reasoning effort, recommended by xAI.