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xAI: Grok 4 Fast

Server-rendered model summary page for indexing/share previews. Use the interactive explorer for full filtering and comparison.

Match confidence: UnmatchedSource type: openrouter_only
Context window
2M
Arena overall rank
Input price
$0.000 / 1M
Output price
$0.000 / 1M

Identifiers & provenance

Primary ID
x-ai/grok-4-fast
OpenRouter ID
x-ai/grok-4-fast
Canonical slug
x-ai/grok-4-fast

Source semantics

  • Arena rank is a human-preference leaderboard signal, not a universal truth metric.
  • OpenRouter usage/popularity reflects adoption/traffic, not benchmark quality.
  • Pricing fields may differ by provider and can include extra modes beyond prompt/completion.

Read more on Methodology & data sources.

Description

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)

Raw fields snapshot

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  "created": 1758240090,
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  "hugging_face_id": "",
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    "tokenizer": "Grok",
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  "openrouter_raw": {
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xAI: Grok 4 Fast · NNZen