GPT-5 Codex
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GPT-5 Codex vs Gemini 2.5 Pro (I/O Edition)
Compare GPT-5 Codex by OpenAI against Gemini 2.5 Pro (I/O Edition) by Google AI, in 4 community votes, gpt-5 codex and gemini 2.5 pro (i/o edition) are closely matched, tested across 32 shared challenges. Updated April 2026.
Which is better, GPT-5 Codex or Gemini 2.5 Pro (I/O Edition)?
GPT-5 Codex and Gemini 2.5 Pro (I/O Edition) are closely matched based on 4 community votes. Compare their real outputs side by side below.
Key Differences Between GPT-5 Codex and Gemini 2.5 Pro (I/O Edition)
GPT-5 Codex is made by openai while Gemini 2.5 Pro (I/O Edition) is from google. In community voting, In 4 community votes, GPT-5 Codex and Gemini 2.5 Pro (I/O Edition) are closely matched.
In 4 community votes, GPT-5 Codex and Gemini 2.5 Pro (I/O Edition) are closely matched. Gemini 2.5 Pro (I/O Edition) leads in Reasoning. Based on blind community voting from the Rival open dataset of 4+ human preference judgments for this pair.
Reasoning: Gemini 2.5 Pro (I/O Edition) wins 67% of votes
Our Verdict
GPT-5 CodexWinner
Gemini 2.5 Pro (I/O Edition)Runner-up
Votes are tied. GPT-5 Codex is newer and likely incorporates more recent improvements.
Gemini 2.5 Pro (I/O Edition) particularly excels in Reasoning.
Too close to call
Writing DNA
Style Comparison
Similarity
99%
GPT-5 Codex uses 14.6x more emoji
GPT-5 Codex
Gemini 2.5 Pro (I/O Edition)
64%Vocabulary58%
17wSentence Length16w
0.38Hedging0.38
2.3Bold5.8
3.5Lists5.0
0.15Emoji0.00
0.49Headings0.63
0.05Transitions0.01
Based on 13 + 16 text responses
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