grok-code-fast-1
Grok Code Fast 1 (xAI)
Yes — Grok Code Fast 1 is retired. xAI shut it down on May 15, 2026; API requests to it now fail. The recommended replacement is Grok Build 0.1.
xAI's first dedicated coding model, given away free through GitHub Copilot and Cursor for long enough to build real habits around it. It is the only id in the May 2026 wave that does not route to grok-4.3 - coding traffic goes to grok-build-0.1 instead.
The facts
| Provider | xAI |
|---|---|
| Model id | grok-code-fast-1 |
| Released | — |
| Deprecated | date not published |
| Shutdown | May 15, 2026 · 80 days ago |
| Status | Retired |
| Last verified | August 3, 2026 |
What to use instead
The context window shrinks from 256k on both sides, but grok-build-0.1 is a different model rather than a tuned reasoning effort, so agent prompts are worth re-testing rather than lifting straight across.
What parameters grok-build-0.1 accepts on modelparams.dev
Change the id
In most cases the migration is one string. Check the parameter differences before you ship — newer models drop older sampling knobs more often than they add them.
- "model": "grok-code-fast-1"
+ "model": "grok-build-0.1"
Frequently asked questions
- When did xAI Grok Code Fast 1 shut down?
- xAI Grok Code Fast 1 shut down on May 15, 2026. API requests to it fail from that date onward.
- What replaces xAI Grok Code Fast 1?
- xAI recommends Grok Build 0.1 (`grok-build-0.1`) as the replacement for xAI Grok Code Fast 1. The context window shrinks from 256k on both sides, but grok-build-0.1 is a different model rather than a tuned reasoning effort, so agent prompts are worth re-testing rather than lifting straight across.
- Is xAI Grok Code Fast 1 still available?
- No. xAI Grok Code Fast 1 is retired and no longer served — it was shut down on May 15, 2026. Calls to it return an error.
- How do I migrate from xAI Grok Code Fast 1 to grok-build-0.1?
- Swap the model id in your API call: replace "grok-code-fast-1" with "grok-build-0.1". The context window shrinks from 256k on both sides, but grok-build-0.1 is a different model rather than a tuned reasoning effort, so agent prompts are worth re-testing rather than lifting straight across.
Sources
- Grok Model Retirement on May 15, 2026 · docs.x.ai · accessed August 3, 2026
Found something wrong? The data is one YAML file — edit it on GitHub.
This page, for machines
Drop the badge in a README so it turns red the day this model is retired:
[](https://modeldeprecations.dev/xai/grok-code-fast-1)