GPT-5.1-Codex
Nothing here. The model returned empty. We stared at it for a while.
GPT-5.1-Codex vs Claude Opus 4
Compare GPT-5.1-Codex by OpenAI against Claude Opus 4 by Anthropic, in 1 community votes, gpt-5.1-codex wins 100% of head-to-head duels, context windows of 400K vs 200K, tested across 34 shared challenges. Updated April 2026.
Which is better, GPT-5.1-Codex or Claude Opus 4?
GPT-5.1-Codex is the better choice overall, winning 100% of 1 blind community votes on Rival. GPT-5.1-Codex costs $1.25/M input tokens vs $15/M for Claude Opus 4. Context windows: 400K vs 200K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-5.1-Codex and Claude Opus 4
GPT-5.1-Codex is made by openai while Claude Opus 4 is from anthropic. GPT-5.1-Codex has a 400K token context window compared to Claude Opus 4's 200K. On pricing, GPT-5.1-Codex costs $1.25/M input tokens vs $15/M for Claude Opus 4. In community voting, In 1 community votes, GPT-5.1-Codex wins 100% of head-to-head duels.
In 1 community votes, GPT-5.1-Codex wins 100% of head-to-head duels. Based on blind community voting from the Rival open dataset of 1+ human preference judgments for this pair.
Our Verdict
GPT-5.1-CodexWinner
Claude Opus 4Runner-up
Pick GPT-5.1-Codex. In 1 blind votes, GPT-5.1-Codex wins 100% of the time. That's not luck.
GPT-5.1-Codex is 7.5x cheaper per token — worth considering if cost matters.
Clear winner
Writing DNA
Style Comparison
Similarity
94%
Claude Opus 4 uses 11.2x more emoji
GPT-5.1-Codex
Claude Opus 4
70%Vocabulary64%
17wSentence Length62w
0.39Hedging0.52
3.4Bold4.4
3.5Lists9.1
0.00Emoji0.11
0.50Headings1.87
0.38Transitions0.27
Based on 14 + 16 text responses
vsAsk them anything yourself
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
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