Updated Nov 13, 2025

Our Verdict

GPT-5.1-Codex

Claude Sonnet 4Runner-up

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

Slight edge

Writing DNA

Style Comparison

Similarity

94%

Claude Sonnet 4 uses 87.9x more emoji

GPT-5.1-Codex

Claude Sonnet 4

70%Vocabulary62%

17wSentence Length111w

0.39Hedging0.40

3.4Bold5.0

3.5Lists9.3

0.00Emoji0.88

0.50Headings2.16

0.38Transitions0.33

Based on 14 + 17 text responses

vs

Ask them anything yourself

GPT-5.1-Codex

Claude Sonnet 4

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

Download the free preview or get all 58 slides for $49

FAQ

Common questions

Keep going

GPT-5.1-Codex vs MiniMax M1New provider

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

GPT-5.1-Codex vs Aurora AlphaNew provider

GPT-5.1-CodexvsClaude Sonnet 4

33 fights queued

Why GPT-5.1-Codex?

1.6x cheaper overall$1.25/M in · $10.00/M out

2x more context400K

Leads 1 of 1 benchmarks

6 months newerNov 2025

Why Claude Sonnet 4?

Dead even. This one's a coin flip.

GPT-5.1-CodexClaude Sonnet 4

Input price

$1.25/M

$3.00/M

Output price

$10.00/M

$15.00/M

Context

400K

200K

Released

Nov 2025

May 2025

Benchmarks1 common

SWE-bench Verified

73.7%+1.4%

72.7%

Favorites

GPT-5.1-CodexClaude Sonnet 4

Movie

The Shawshank Redemption

The Shawshank Redemption

2001: A Space Odyssey

2001: A Space Odyssey

Album

Kind of Blue

Kind of Blue

Book

Le città invisibili

Le città invisibili

Gödel, Escher, Bach

Gödel, Escher, Bach

Douglas R. Hofstadter

City

Kyoto

Istanbul

Game

Portal 2

Portal 2

Shooter, Puzzle4.6

Portal 2

Portal 2

Shooter, Puzzle4.6

12 / 33

01

Logic Puzzlereasoning

Tests an AI's ability to solve a simple but potentially confusing logic puzzle

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025text

I need to think through this step-by-step.

Given information:

Sally is a girl
Sally has 3 brothers
Each brother has 2 sisters

Let me work out how many sisters are in the family total.

If each of Sally's 3 brothers has 2 sisters, and all the brothers are in the same family, then there must be 2 sisters total in the family.

Since Sally is one of those sisters, and there are 2 sisters total, Sally must have 1 sister.

Therefore, Sally has 1 sister.

Try this prompt

Vote

2 / 33

02

Math Misconception Testreasoning

Tests an AI's understanding of number representation

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025text

No, 9.11 is not greater than 9.9.

To compare these decimal numbers:

9.11 = 9.11
9.9 = 9.90

Since both numbers have the same whole number part (9), we compare the decimal parts:

0.11 vs 0.90
11 hundredths vs 90 hundredths

Therefore, 9.9 is greater than 9.11.

Try this prompt

Vote

3 / 33

03

Stochastic Consistency Testanalysis

Tests an AI's randomness and creativity

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025text

Here are 5 jokes for you:

Why don't scientists trust atoms? Because they make up everything!
I told my wife she was drawing her eyebrows too high. She looked surprised.
Why don't eggs tell jokes? They'd crack each other up!
I'm reading a book about anti-gravity. It's impossible to put down!
Why did the scarecrow win an award? He was outstanding in his field!

All 5 jokes are unique - each one has a different setup, punchline, and comedic concept. They cover different types of wordplay: scientific puns (#1, #4), visual humor (#2), food puns (#3), and agricultural wordplay (#5).

Try this prompt

Vote

4 / 33

04

SVG Layout Challengeimage generation

Tests an AI's ability to generate vector graphics

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025svg

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025svg

Try this prompt

Vote

5 / 33

05

Xbox Controller SVG Artimage generation

Tests an AI's ability to create detailed SVG illustrations of gaming hardware

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025svg

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025svg

Try this prompt

Vote

6 / 33

06

Generate a Stand-Up Routineconversation

Tests an AI's humor and creative writing ability

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025text

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

Sponsored

7 / 33

07

Pokémon Battle UI Recreationweb design

Recreate an interactive, nostalgic Pokémon battle UI in a single HTML file.

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

8 / 33

08

Mario Level UI Recreationweb design

Recreate an interactive, classic Mario level in a single HTML file.

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025website

Try this prompt

Vote

9 / 33

09

Linear App Cloneweb design

Tests an AI's ability to replicate an existing UI with Tailwind CSS

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025website

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

10 / 33

10

Interactive Catan Boardweb design

Tests an AI's ability to create interactive web elements

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025website

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

11 / 33

11

World Map SVGimage generation

Tests an AI's ability to create a detailed world map in SVG format

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025svg

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025svg

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

12 / 33

12

Random Tailwind Webappweb design

Generate a single-page, self-contained HTML webapp using Tailwind CSS for a randomly chosen category/industry/niche.

GPT-5.1-Codex

GPT-5.1-Codex

Openai · Nov 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Claude Sonnet 4

Claude Sonnet 4

Anthropic · May 2025website

Nothing here. The model returned empty. We stared at it for a while.

Try this prompt

Vote

This matchup has more rounds

21+ more head-to-head results. Free. Not a trick.

Free account. No card required. By continuing, you agree to Rival's Terms and Privacy Policy