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x-ai/grok-4-fast
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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)
9/19/2025
2,000,000 tokens
#52 Text (Japanese)
Specifications
Modalities
Input
text
image
Output
text
Supported Parameters
include_reasoning
logprobs
max_tokens
reasoning
response_format
seed
structured_outputs
temperature
tool_choice
tools
top_logprobs
top_p
Max Output Tokens
30,000Leaderboard
Text
🏆OverallELO: 1,405
#81🇯🇵JapaneseELO: 1,356
#52🇨🇳ChineseELO: 1,443
#71🇰🇷KoreanELO: 1,343
#76🇬🇧EnglishELO: 1,415
#86frenchELO: 1,443
#53germanELO: 1,383
#77spanishELO: 1,413
#52russianELO: 1,399
#74💻CodingELO: 1,438
#96🧮MathELO: 1,411
#67✍️Creative WritingELO: 1,383
#70📝Instruction FollowingELO: 1,389
#88🌶️Hard PromptsELO: 1,414
#96💬Multi-TurnELO: 1,407
#79Code
🏆OverallELO: 1,147
#55