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.

MF✕ Retired Grok 4 Fast Reasoning 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 → https://llmstatus.ai/sign-up