Grok 4.1 Fast changelog

Every change to Grok 4.1 Fast that Modelpeers has recorded, newest first, each with the source it came from. The record starts May 15, 2026.

May 2026

Grok 4.1 Fast, 4, Code Fast 1

5 products from SpaceXSI

Retired

xAI retires older Grok models, requests redirect to Grok 4.3

On May 15, 2026 xAI retired grok-4-1-fast, grok-4-fast, grok-4-0709, grok-code-fast-1, grok-3 and grok-imagine-image-pro. Requests to these slugs redirect to grok-4.3 (or grok-build-0.1 for grok-code-fast-1) and are billed at grok-4.3 rates of $1.25 input and $2.50 output per 1M tokens.

After

grok-4.3 at $1.25 / $2.50 per 1M tokens

Who is affected:
Apps still calling the retired Grok slugs, which now get a different model at a different price.
Action needed:
Set the model explicitly to grok-4.3 with the reasoning effort you want, or grok-build-0.1 for coding.

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