Gemini 3.1 Pro Preview vs GPT-5 Codex

Compare Gemini 3.1 Pro Preview by Google AI against GPT-5 Codex by OpenAI, tested across 49 shared challenges. Updated April 2026.

Which is better, Gemini 3.1 Pro Preview or GPT-5 Codex?

Gemini 3.1 Pro Preview and GPT-5 Codex are both competitive models. Compare their real outputs side by side below.

Key Differences Between Gemini 3.1 Pro Preview and GPT-5 Codex

Gemini 3.1 Pro Preview is made by google while GPT-5 Codex is from openai.

Our Verdict
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview
GPT-5 Codex
GPT-5 Codex

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call
Writing DNA

Style Comparison

Similarity
99%

GPT-5 Codex uses 14.6x more emoji

Gemini 3.1 Pro Preview
GPT-5 Codex
54%Vocabulary64%
18wSentence Length17w
0.29Hedging0.38
4.9Bold2.3
3.3Lists3.5
0.00Emoji0.15
0.72Headings0.49
0.14Transitions0.05
Based on 23 + 13 text responses
vs

Ask them anything yourself

Gemini 3.1 Pro PreviewGPT-5 Codex

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
FAQ

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