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xAI: Grok 4 Fast

Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model on xAI's [news post](http://x.ai/news/grok-4-fast). Reasoning can be enabled/disabled using the `reasoning` `enabled` parameter in the API. [Learn more in our docs](https://openrouter.ai/docs/use-cases/reasoning-tokens#controlling-reasoning-tokens)

Context Window

2.0M

Input Price

$0.2000/M tokens

Output Price

$0.5000/M tokens

Modality

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Pricing Breakdown

Cost per million tokens for input and output

Input$0.2000/M tokens

Output$0.5000/M tokens

Cost Example: Processing 10,000 input tokens and generating 1,000 output tokens would cost approximately $0.002500

Context Window Size

Maximum tokens the model can process in a single request

Context Window2.0M tokens

100% of 1M max

~1500K

Words Equivalent

~1000

Pages of Text

~20000

Code Functions

Best Use Cases

What this model excels at

MathReasoningAnalysisVisionImage-analysisMultimodal

Related Categories:

Data Analysis Image Generation

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