Grok 4.1 Fast Reasoning

API ID grok-4-1-fast-reasoning

grok-4-1-fast-reasoning was an xAI model.

Status: Retired
Released: —
Shutdown: May 15, 2026
Replacement: Grok 4.3grok-4.3

grok-4-1-fast-reasoning stopped serving on May 15, 2026. Requests to it are now redirected to grok-4.3 and billed at its price.

How to migrate to Grok 4.3

Benchmarks

Scores as each source published them

Comparing with Grok 4 Fast Reasoning, the previous model in this line. A score is compared only with the same benchmark from the same source, at the same setting where both have it. Full comparison: prices, limits, features

Arena

Arena	Grok 4.1 Fast Reasoning	Grok 4 Fast Reasoning	Change	Rank	Date	Source
Text By category Math 1421 rank 127 vs 1411 (+10, within range) Creative writing 1415 rank 88 vs 1384 (+31) Instruction following 1402 rank 143 vs 1389 (+13, within range) Hard prompts 1441 rank 130 vs 1414 (+27) Long prompts 1422 rank 136 vs 1413 (+9, within range) Multi-turn 1413 rank 143 vs 1405 (+8, within range) Expert 1438 rank 136 vs 1422 (+16, within range)	1430 ±3	1405 ±5	+25	115 of 415 57,558 votes	Oct 13, 2026	source
Text: Coding	1461 ±6	1439 ±9	+22	137 of 410 13,927 votes	Oct 13, 2026	source
WebDev	1242 ±11	1159 ±27	+83	132 of 142 5,491 votes	Oct 13, 2026	source
Vision	1196 ±7	not rated		94 of 165 13,373 votes	Oct 9, 2026	source
Search	1195 ±5	1161 ±5	+34	23 of 42 85,919 votes	Oct 13, 2026	source

Rated as grok-4-1-fast-search; Grok 4 Fast Reasoning as grok-4-fast-search. Ratings come from people voting between two anonymous answers; Text, Vision and Search are style-controlled, as on arena.ai. Data: Arena (arena.ai), CC BY 4.0.

On cloud platforms

All platform dates

Platform	Platform ID	State	Shutdown	Time left	Replacement	Source
Microsoft Foundryversion 1	grok-4-1-fast-reasoning	Active	none announced		—	source

Read daily from each platform's own pages. The shutdown date and countdown on this page use xAI's own date.

Price history

USD per 1M tokens, standard tier

No price history yet.

Prices

USD per 1M tokens, every type and band, by tier

No published prices.

Changelog

Changes we detected on xAI's pages

Oct 5, 2026
Retired
grok-4-1-fast-reasoning has been retired
Info

Last checked Oct 15, 2026, 2:00 am ET · Sources: xAI pricing, xAI notices, xAI release notes