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[ARTICLE · art-155005] src=llmstatus.ai ↗ pub= topic=large-language-models verified=true sentiment=· neutral

Grok 4 Fast (Reasoning) retired 2026-05-01 → Grok 4.1 Fast (Reasoning)

Microsoft has retired the Azure-hosted Grok 4 Fast (Reasoning) model, listed as grok-4-fast-reasoning, with a retirement date of 2026-05-01, and points users to Grok 4.1 Fast (Reasoning) as the replacement. The retired model carried a 2,000k context window and 30k max output with text and image input, and the lifecycle notice notes Azure hosting may differ from provider-direct availability. The change matters for developers whose code calls the model identifier, since calls to grok-4-fast-reasoning will need to migrate to the Grok 4.1 Fast (Reasoning) successor.

read1 min views4 publishedOct 22, 2026
Grok 4 Fast (Reasoning) retired 2026-05-01 → Grok 4.1 Fast (Reasoning)
Image: Llmstatus (auto-discovered)

MF✕ Retired

Microsoft · grok-4-fast-reasoning

Azure-hosted lifecycle (may differ from provider-direct). 

[Provider statement →](https://models.dev/azure/grok-4-fast-reasoning)

groktext+image2000k context30k max out

also matches:

`grok-4-fast-reasoning`` microsoft/grok-4-fast-reasoning`
[provider announcement →](https://models.dev/azure/grok-4-fast-reasoning)

Does your code call Grok 4 Fast (Reasoning)?

$ curl -fsSL https://llmstatus.ai/install.sh | bash

Then mm status in any repo — it finds every model you use and flags the ones on a clock. No account, nothing uploaded.

Get alerted before it retires →

source & further reading
llmstatus.ai — original article GPT-3.5 Turbo (0301) retired 2024-09-13 → GPT-3.5 Turbo Qwen3 14B deprecated Qwen3-Omni Flash Realtime deprecated
── more in #large-language-models 4 stories · sorted by recency
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