Is grok-4-fast-reasoning deprecated?

Q: Is grok-4-fast-reasoning deprecated?

Yes — deprecated. Retired 2026-05-15 — 79 days ago. Requests to this identifier are expected to fail.

DEPRECATED

Retired 2026-05-15 — 79 days ago. Requests to this identifier are expected to fail.

state=dead sunset=2026-05-15 days_remaining=-79 severity=critical sources=litellm evidence_tier=catalog confirmed_by_endpoint=false documented_by_provider=false replacement=none corroborated=single-source divergent_fields=none checked=2026-08-02 01:41Z

xai/grok-4-fast-reasoning

Vendor: xai. Tracked by 1 of 5 sources.

What each source reports

**endpoint** = the provider's own machine-readable API, the strongest evidence. **provider docs** = the provider's own documentation, read by a model — first-party content, inferred reading. Unlabelled rows are third-party catalogs. Where sources disagree both values are shown rather than silently reconciled.
Source	ID	Context	Max out	In $/Mtok	Out $/Mtok	Sunset
litellm	xai/grok-4-fast-reasoning	—	—	$0.2	$0.5	2026-05-15

Change history

Severity	Change	What	Detected
info	deprecated	xai/grok-4-fast-reasoning: retires 2026-05-15 (78 days ago)	2026-08-01
info	deprecated	xai/grok-4-fast-reasoning: deprecation announced for 2026-05-15 (date already passed)	2026-06-05