GPT-5.1-Codex-Mini vs Grok 3

Compare GPT-5.1-Codex-Mini by OpenAI against Grok 3 by xAI, context windows of 400K vs 128K, tested across 53 shared challenges. Updated April 2026.

Which is better, GPT-5.1-Codex-Mini or Grok 3?

GPT-5.1-Codex-Mini and Grok 3 are both competitive models. Context windows: 400K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between GPT-5.1-Codex-Mini and Grok 3

GPT-5.1-Codex-Mini is made by openai while Grok 3 is from xai. GPT-5.1-Codex-Mini has a 400K token context window compared to Grok 3's 128K.

Our Verdict
GPT-5.1-Codex-Mini
GPT-5.1-Codex-Mini
Grok 3
Grok 3Runner-up

No community votes yet. On paper, GPT-5.1-Codex-Mini has the edge — newer, bigger context window.

Too close to call
Writing DNA

Style Comparison

Similarity
91%

Grok 3 uses 3.9x more emoji

GPT-5.1-Codex-Mini
Grok 3
65%Vocabulary49%
20wSentence Length18w
0.56Hedging0.94
3.3Bold2.5
3.4Lists3.0
0.00Emoji0.04
0.08Headings0.65
0.05Transitions0.08
Based on 13 + 17 text responses
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GPT-5.1-Codex-MiniGrok 3

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
Free preview13 of 58 slides
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