What is the difference between Claude Opus 5 and GPT-5.1 Codex Max?

Claude Opus 5 is developed by Anthropic while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 5 or GPT-5.1 Codex Max?

It depends on your use case. Claude Opus 5 and GPT-5.1 Codex Max each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

How can I compare Claude Opus 5 and GPT-5.1 Codex Max on Rival?

This page shows a side-by-side comparison of Claude Opus 5 and GPT-5.1 Codex Max across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

What is the difference between Claude Opus 5 and GPT-5.1 Codex Max?

Claude Opus 5 is developed by Anthropic while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 5 or GPT-5.1 Codex Max?

It depends on your use case. Claude Opus 5 and GPT-5.1 Codex Max each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

How can I compare Claude Opus 5 and GPT-5.1 Codex Max on Rival?

This page shows a side-by-side comparison of Claude Opus 5 and GPT-5.1 Codex Max across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Claude Opus 5 vs GPT-5.1 Codex Max: Which Is Better?

Updated Jul 2026

Our Verdict

Claude Opus 5

GPT-5.1 Codex Max

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

API pricing

Cost per 1M tokens

Claude Opus 5

Input

$5.00

Output

$25.00

GPT-5.1 Codex Max

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

69%

Claude Opus 5 uses 1.7x more emoji

Claude Opus 5

GPT-5.1 Codex Max

54%Vocabulary60%

21wSentence Length16w

0.40Hedging0.36

3.9Bold2.3

1.9Lists4.2

0.02Emoji0.00

0.71Headings0.12

0.05Transitions0.03

Based on 27 + 13 text responses

Research

What we learned reading every model

Claude Opus 5 and GPT-5.1 Codex Max have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

GPT-5.1 Codex Max vs MiniMax M3New provider

GPT-5.1 Codex Max vs Gemini 2.5 Pro Preview 06-05New provider

GPT-5.1 Codex Max vs Claude Opus 4Cross-provider

Updated Jul 2026

Our Verdict

Claude Opus 5

GPT-5.1 Codex Max

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

API pricing

Cost per 1M tokens

Claude Opus 5

Input

$5.00

Output

$25.00

GPT-5.1 Codex Max

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

69%

Claude Opus 5 uses 1.7x more emoji

Claude Opus 5

GPT-5.1 Codex Max

54%Vocabulary60%

21wSentence Length16w

0.40Hedging0.36

3.9Bold2.3

1.9Lists4.2

0.02Emoji0.00

0.71Headings0.12

0.05Transitions0.03

Based on 27 + 13 text responses

Research

What we learned reading every model

Claude Opus 5 and GPT-5.1 Codex Max have opinions about your brand too.Ask 10 models what they tell people about you. Verbatim receipts.Run the mirror

FAQ

Common questions

Keep exploring

More comparisons

GPT-5.1 Codex Max vs MiniMax M3New provider

GPT-5.1 Codex Max vs Gemini 2.5 Pro Preview 06-05New provider

GPT-5.1 Codex Max vs Claude Opus 4Cross-provider