Is xAI Grok 4 Fast (reasoning) deprecated?
No longer available. xAI shut Grok 4 Fast (reasoning) down on 2026-05-15 — calls to it fail.
What kind of model is this?
Tags describe what Grok 4 Fast (reasoning) takes in, what it is built for and how you can get it. Modality, access and language tags follow xAI's own documentation; tier and use-case tags are our reading of the line-up.
- Modality
- Use case
- Tier
- Access
Specifications
- Input price
- unknown
- Output price
- unknown
- Price band
- unknown
- Context window
- unknown
- Max output
- unknown
- Input
- Text
- Output
- Text
- Knowledge cutoff
- unknown
- Tool use
- unknown
- Structured output
- unknown
- Weights licence
- not published
- Model maker
- xAI
“unknown” means the figure has not been published, or we have not verified it yet — never that the answer is no. “not published” under the weights licence means this model is not offered with downloadable weights. The price band is ours: it bands the blended price (three parts input to one part output) as budget (≤ $0.50), standard (≤ $3), premium (≤ $12) or flagship.
Lifecycle
- Released unknown
- Deprecated
- Retired
What is it good for?
No editorial profile for this model yet. The specifications above come from xAI's own documentation and the suggestions below are derived from the data — shared tags, tier and price band — not written by hand.
What to use instead of Grok 4 Fast (reasoning)
-
Grok 4.20 (reasoning) Derived
Same provider, same tier (mid-tier); shares chat, coding, reasoning and agents.
$1.25 in · $2.50 out / M tokens 1M context
-
Claude Sonnet 4.5 Derived
Alternative from Amazon Bedrock, same tier (mid-tier); shares chat, coding, reasoning and agents.
$3.00 in · $15.00 out / M tokens 200K context
-
Claude Sonnet 4.6 Derived
Alternative from Amazon Bedrock, same tier (mid-tier); shares chat, coding, reasoning and agents.
$3.00 in · $15.00 out / M tokens 1M context
-
Claude Sonnet 5 Derived
Alternative from Amazon Bedrock, same tier (mid-tier); shares chat, coding, reasoning and agents.
$2.00 in · $10.00 out / M tokens 1M context
-
Claude Sonnet 4.5 Derived
Alternative from Anthropic, same tier (mid-tier); shares chat, coding, reasoning and agents.
$3.00 in · $15.00 out / M tokens 200K context
Derived suggestions are ranked from the data — shared tags, the same tier and a comparable price band — not from benchmark scores. Check the capability fit yourself: we track lifecycle, price and specifications.
Sources
- docs.x.ai https://docs.x.ai/developers/migration/may-15-retirement
- docs.x.ai https://docs.x.ai/developers/models
Verified against the source on . Dataset snapshot . Providers can change a date without notice — the link above is always the final word.
Common questions
- Is Grok 4 Fast (reasoning) deprecated?
- No longer available. xAI shut Grok 4 Fast (reasoning) down on 2026-05-15 — calls to it fail.
- When does Grok 4 Fast (reasoning) shut down?
- xAI has announced 2026-05-15 as the shutdown date for Grok 4 Fast (reasoning).
- What does Grok 4 Fast (reasoning) cost?
- No public price is listed for Grok 4 Fast (reasoning) in our dataset.
- What can I use instead of Grok 4 Fast (reasoning)?
- Active alternatives include xAI Grok 4.20 (reasoning), Amazon Bedrock Claude Sonnet 4.5, Amazon Bedrock Claude Sonnet 4.6.