What is the difference between Claude Sonnet 4.5 and GPT-5.1-Codex-Mini?

Claude Sonnet 4.5 is developed by Anthropic while GPT-5.1-Codex-Mini is developed by OpenAI. Claude Sonnet 4.5 has a 200K token context window vs GPT-5.1-Codex-Mini's 400K. You can compare their actual outputs across 43 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or GPT-5.1-Codex-Mini?

It depends on your use case. Claude Sonnet 4.5 and GPT-5.1-Codex-Mini each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 43 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4.5 cost compared to GPT-5.1-Codex-Mini?

Claude Sonnet 4.5 costs $3/M input tokens and GPT-5.1-Codex-Mini costs $1.5/M input tokens. GPT-5.1-Codex-Mini is $1.50/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Claude Sonnet 4.5 and GPT-5.1-Codex-Mini on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and GPT-5.1-Codex-Mini 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.

Updated Nov 2025

Claude Sonnet 4.5vsGPT-5.1-Codex-Mini

GPT-5.1-Codex-Mini is cheaper than Claude Sonnet 4.5 at $1.5/M vs $3/M input tokens.

Claude Sonnet 4.5 and GPT-5.1-Codex-Mini compared across 43 shared prompts
Spec	Claude Sonnet 4.5	GPT-5.1-Codex-Mini
Input price	$3/M tokens	$1.5/M tokens
Output price	$15/M tokens	$6/M tokens
Context window	200K tokens	400K tokens
Weights	Closed	Closed
Free API (OpenRouter)	No	No
Released	Sep 2025	Nov 2025