# Grok 4 Fast

Grok 4 Fast is an AI model released by SpaceXAI on Sep 19 2025.

## Facts

| Field | Value |
| --- | --- |
| Model | Grok 4 Fast |
| Developer | SpaceXAI |
| Release date | Friday, Sep 19 2025 |
| Licensing | Proprietary |

## Questions and answers

### When was Grok 4 Fast released?

Grok 4 Fast was released by SpaceXAI on Friday, Sep 19 2025.

### Who made Grok 4 Fast?

Grok 4 Fast was built by SpaceXAI. Elon Musk's AI company building the Grok series of models. Founded in 2023 as xAI, now part of SpaceX. Cursor (Anysphere) and its Composer coding models were acquired in 2026 and are tracked here.

### Is Grok 4 Fast open source?

No. Grok 4 Fast is a proprietary model. The weights are not published — it is available only through the provider's own API, apps, or partner platforms.

### What came before and after Grok 4 Fast?

SpaceXAI's previous tracked release was Grok Code Fast 1 on Aug 28 2025, 22 days earlier. It was followed by Composer on Oct 29 2025.


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Canonical page: https://aireleasetracker.com/model/xai/grok-4-fast
Full dataset: https://aireleasetracker.com/llms-full.txt · JSON: https://aireleasetracker.com/models.json
Source: AI Release Tracker (https://aireleasetracker.com). Benchmark scores are the figures published by the releasing lab at launch.