Azure AI Foundry
grok-4-fast-reasoning model retirement
Stopped working
On May 1, 2026, Azure AI Foundry will retire model grok-4-fast-reasoning. Any calls directed to model grok-4-fast-reasoning after that day will fail.
What to use instead of grok-4-fast-reasoning
Migrate to grok-4-1-fast-reasoning, which is named first and stops working on May 19, 2027. No replacement that holds is named yet.
Facts
- API
- Azure AI Foundry
*.services.ai.azure.com - Model
grok-4-fast-reasoning- Kind
- Model retirement
- Takes effect
- May 1, 2026
- Calls after that day
- Fail
- Source
- Deprecations page
- Last updated
- Verified
- , against Azure AI Foundry's own pages
Questions
When does grok-4-fast-reasoning shut down?
Calls to the model grok-4-fast-reasoning on Azure AI Foundry stopped working on May 1, 2026.
What happens to calls after May 1, 2026?
They have failed since May 1, 2026.
How do I find the calls this hits in my code?
Okapi reads your repository, finds the calls this change hits and opens a pull request with the fix. It never commits to your branches: every change comes as a pull request you review.
grok-4-fast-reasoning on other APIs 1
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xAI
grok-4-fast-reasoningModel retirement Redirected
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You fixed this one by hand.
Okapi opens the pull request with the fix before the next breaking change reaches your code.