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Grok 4 Fast

Multimodal
xAI

Grok 4 Fast is a high-speed variant of Grok-4, optimized for fast inference while maintaining strong reasoning capabilities. Offers improved throughput and lower latency compared to the standard Grok-4.

Key Specifications

Parameters
-
Context
2.0M
Release Date
August 27, 2025
Average Score
81.8%

Timeline

Key dates in the model's history
Announcement
August 27, 2025
Last Update
January 22, 2026
Today
March 25, 2026

Technical Specifications

Parameters
-
Training Tokens
-
Knowledge Cutoff
-
Family
-
Capabilities
MultimodalZeroEval

Pricing & Availability

Input (per 1M tokens)
$0.20
Output (per 1M tokens)
$0.50
Max Input Tokens
2.0M
Max Output Tokens
30.0K
Supported Features
Function CallingStructured OutputCode ExecutionWeb SearchBatch InferenceFine-tuning

Benchmark Results

Model performance metrics across various tests and benchmarks

Reasoning

Logical reasoning and analysis
GPQA
AccuracySelf-reported
86.0%

Other Tests

Specialized benchmarks
SimpleQA
AccuracySelf-reported
95.0%
HMMT 2025
AccuracySelf-reported
93.0%
AIME 2025
AccuracySelf-reported
92.0%
LiveCodeBench
AccuracySelf-reported
80.0%
BrowseComp
AccuracySelf-reported
45.0%

License & Metadata

License
proprietary
Announcement Date
August 27, 2025
Last Updated
January 22, 2026

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