What is the difference between Gemini 2.5 Flash Preview and GPT-5.1 Codex Max?

Gemini 2.5 Flash Preview is developed by Google AI while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 27 challenges on Rival to see how they differ in practice.

Which is better, Gemini 2.5 Flash Preview or GPT-5.1 Codex Max?

It depends on your use case. Gemini 2.5 Flash Preview and GPT-5.1 Codex Max each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 27 challenges so you can judge which fits your needs best.

How can I compare Gemini 2.5 Flash Preview and GPT-5.1 Codex Max on Rival?

This page shows a side-by-side comparison of Gemini 2.5 Flash Preview 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 Gemini 2.5 Flash Preview and GPT-5.1 Codex Max?

Gemini 2.5 Flash Preview is developed by Google AI while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 27 challenges on Rival to see how they differ in practice.

Which is better, Gemini 2.5 Flash Preview or GPT-5.1 Codex Max?

It depends on your use case. Gemini 2.5 Flash Preview and GPT-5.1 Codex Max each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 27 challenges so you can judge which fits your needs best.

How can I compare Gemini 2.5 Flash Preview and GPT-5.1 Codex Max on Rival?

This page shows a side-by-side comparison of Gemini 2.5 Flash Preview 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.

Gemini 2.5 Flash Preview vs GPT-5.1 Codex Max: Which Is Better?

Updated Dec 2025

Our Verdict

GPT-5.1 Codex Max

Gemini 2.5 Flash PreviewRunner-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

Gemini 2.5 Flash Preview

Input

$0.15

Output

$0.60

GPT-5.1 Codex Max

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

54%

Gemini 2.5 Flash Preview uses 9.2x more transitions

Gemini 2.5 Flash Preview

GPT-5.1 Codex Max

51%Vocabulary60%

15wSentence Length16w

0.70Hedging0.36

4.1Bold2.3

3.3Lists4.2

0.00Emoji0.00

0.09Headings0.12

0.24Transitions0.03

Based on 12 + 13 text responses

Research

What we learned reading every model

Gemini 2.5 Flash Preview 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

Gemini 2.5 Flash Preview vs MiniMax M3New provider

Gemini 2.5 Flash Preview vs Grok 3New provider

Gemini 2.5 Flash Preview vs Llama 4 MaverickNew provider

Updated Dec 2025

Our Verdict

GPT-5.1 Codex Max

Gemini 2.5 Flash PreviewRunner-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

Gemini 2.5 Flash Preview

Input

$0.15

Output

$0.60

GPT-5.1 Codex Max

Input

—

Output

—

Writing DNA

Style Comparison

Similarity

54%

Gemini 2.5 Flash Preview uses 9.2x more transitions

Gemini 2.5 Flash Preview

GPT-5.1 Codex Max

51%Vocabulary60%

15wSentence Length16w

0.70Hedging0.36

4.1Bold2.3

3.3Lists4.2

0.00Emoji0.00

0.09Headings0.12

0.24Transitions0.03

Based on 12 + 13 text responses

Research

What we learned reading every model

Gemini 2.5 Flash Preview 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

Gemini 2.5 Flash Preview vs MiniMax M3New provider

Gemini 2.5 Flash Preview vs Grok 3New provider

Gemini 2.5 Flash Preview vs Llama 4 MaverickNew provider