# Grok 4 Fast spotted on models.dev

Grok 4 Fast is a model from xAI, released on 19 Sep 2025. First seen 19 Sep 2026. Catalogues list a 2,000,000 tokens context window. 5 evidence links.

- Kind: Sighting
- Developer: xAI
- Confidence: Supported
- First seen: 2026-09-19T17:20:46.653Z
- Model: [Grok 4 Fast](https://alexgetman.com/models/xai/grok-4-fast/)
- Canonical: https://alexgetman.com/signals/2026/09/19/grok-4-fast/

## Evidence links

- [models.dev · catalogue](https://models.dev/#grok-4-fast)
- [Artificial Analysis · benchmarks](https://artificialanalysis.ai/models)
- [OpenCode · discovery](https://opencode.ai/data/xai/grok-4-fast-non-reasoning)
- [models.dev · catalogue](https://models.dev/#grok-4-fast-non-reasoning)
- [Arena · leaderboards](https://x.ai/news/grok-4-fast)