xAI · deprecated

Grok 4 Fast

Grok 4 Fast is attributed to xAI in the catalog. It accepts text and image input and produces text output. Reported capabilities include reasoning and tool calling.

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Modalities

Token rates

Unavailable

No recent paired token rate available

Context

Released

2025-09-19

Knowledge cutoff

Jan 1, 2025

Where to use it

1 observed offerings · token prices in USD per million where available

Estimate your workload cost

ZenMux

x-ai/grok-4-fast

deprecated

Input

$0.20

Output

$0.50

Cache

$0.05

Context

Max output

64K

Reasoning: Yes
Tool calling: Yes
Structured output: No
Temperature: Unknown

Historical price

Limits and capabilities reflect each provider’s listed offering. Unknown means support was not reported.

Provider / API ID	Status	Context	Max output	Input	Output	Cache read	Reasoning	Tools	Structured	Temperature
ZenMux x-ai/grok-4-fast	deprecatedHistorical price	2M	64K	$0.20	$0.50	$0.05	Yes	Yes	No	Unknown

Capabilities and limits

Input: text, image
Output: text
Max output: 64K
Weights: Closed (source-reported)
Release: 2025-09-19
Knowledge cutoff: Jan 1, 2025
Family: grok

Reasoning · Tool calling · Vision

Provider-specific limits and support can differ.

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Evaluate quality and latency on examples from your intended use before choosing a model.

Explore available evidence

Models to compare

Candidates match reported specifications; they are not tested replacements.

Grok 4.20xAI · 2M contextCompare →Grok 4.20 Multi-AgentxAI · 2M contextCompare →Grok 4.20 Beta ReasoningxAI · 2M contextCompare →

Model and price history

Price history (3 observations)

Date	Provider	Input / output
2026-09-19	ZenMux	$0.20 / $0.50
2026-09-18	ZenMux	$0.20 / $0.50
2026-09-17	ZenMux	$0.20 / $0.50