xAIClosed Weights

Grok-4-Fast-Reasoning

xai/grok-4-fast-reasoning

Best Input Price

$0.20 / 1M

Fast Grok model for responsive chat, reasoning, and tool-assisted work

Context Window

2,000,000 tokens

Reasoning

Supported

Tool Calling

Supported

Released

2025-09-16

Inference Providers (1)

Provider	Model ID	Context	Input / 1M	Output / 1M	Action
Poe	xai/grok-4-fast-reasoning	2,000,000	$0.20	$0.50	Docs ↗