What is the difference between Claude Sonnet 4 and GPT-5.1 Codex Max?

Claude Sonnet 4 is developed by Anthropic while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4 or GPT-5.1 Codex Max?

It depends on your use case. Claude Sonnet 4 and GPT-5.1 Codex Max each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How can I compare Claude Sonnet 4 and GPT-5.1 Codex Max on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4 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 Sonnet 4 and GPT-5.1 Codex Max?

Claude Sonnet 4 is developed by Anthropic while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4 or GPT-5.1 Codex Max?

It depends on your use case. Claude Sonnet 4 and GPT-5.1 Codex Max each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How can I compare Claude Sonnet 4 and GPT-5.1 Codex Max on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4 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 Sonnet 4 vs GPT-5.1 Codex Max: Which Is Better?

Updated Dec 2025

Our Verdict

GPT-5.1 Codex Max

Claude Sonnet 4Runner-up

No community votes yet. On paper, GPT-5.1 Codex Max has the edge — bigger model tier, newer.

Too close to call

API pricing

Cost per 1M tokens

Claude Sonnet 4

Input

$3.00

Output

$15.00

GPT-5.1 Codex Max

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

38%

Claude Sonnet 4 uses 87.9x more emoji

Claude Sonnet 4

GPT-5.1 Codex Max

62%Vocabulary60%

111wSentence Length16w

0.40Hedging0.36

5.0Bold2.3

9.3Lists4.2

0.88Emoji0.00

2.16Headings0.12

0.33Transitions0.03

Based on 17 + 13 text responses

Research

What we learned reading every model

Claude Sonnet 4 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 Claude Opus 4Cross-provider

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

Updated Dec 2025

Our Verdict

GPT-5.1 Codex Max

Claude Sonnet 4Runner-up

No community votes yet. On paper, GPT-5.1 Codex Max has the edge — bigger model tier, newer.

Too close to call

API pricing

Cost per 1M tokens

Claude Sonnet 4

Input

$3.00

Output

$15.00

GPT-5.1 Codex Max

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

38%

Claude Sonnet 4 uses 87.9x more emoji

Claude Sonnet 4

GPT-5.1 Codex Max

62%Vocabulary60%

111wSentence Length16w

0.40Hedging0.36

5.0Bold2.3

9.3Lists4.2

0.88Emoji0.00

2.16Headings0.12

0.33Transitions0.03

Based on 17 + 13 text responses

Research

What we learned reading every model

Claude Sonnet 4 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 Claude Opus 4Cross-provider

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