Grok 4.1 Fast

xai

Grok 4.1 Fast is xAI's best tool-calling model with a 2M context window. It reasons and completes agentic tasks accurately and rapidly, excelling at complex real-world use cases such as customer support and finance. To optimize for speed use this variant. Otherwise, use the reasoning version.

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Capabilities

Tool Use

Image Input

Technical Specifications

Context Window

2,000,000 tokens

Max Output

256,000 tokens

Confidence Scale

2.55x (above average)

Input Cost

$0.20 per 1M tokens

Output Cost

$0.50 per 1M tokens

File Input Limit

20 files

Files in Assistant Messages

Yes

Availability

No account required

$0 per month

Also available in these plans

Free
Free
Plus
$20/mo
Pro
$100/mo
Super
$200/mo