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Grok-4.1 Fast Reasoning

Multimodal
xAI

Grok-4.1 Fast Reasoning is the next generation of fast agents from the xAI API with reasoning mode. A high-speed variant optimized for fast inference with thinking token support. 2M token context window. Multimodal model.

Key Specifications

Parameters
-
Context
2.0M
Release Date
November 16, 2025
Average Score
-

Timeline

Key dates in the model's history
Announcement
November 16, 2025
Last Update
February 12, 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

License & Metadata

License
proprietary
Announcement Date
November 16, 2025
Last Updated
February 12, 2026

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