What is the difference between Claude Opus 4 and GPT-5 Codex?

Claude Opus 4 is developed by Anthropic while GPT-5 Codex is developed by OpenAI. You can compare their actual outputs across 49 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4 or GPT-5 Codex?

It depends on your use case. Claude Opus 4 and GPT-5 Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 49 challenges so you can judge which fits your needs best.

How can I compare Claude Opus 4 and GPT-5 Codex on Rival?

This page shows a side-by-side comparison of Claude Opus 4 and GPT-5 Codex 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 Sep 2025

Claude Opus 4vsGPT-5 Codex

GPT-5 Codex is the newer model, released after Claude Opus 4.

Claude Opus 4 and GPT-5 Codex compared across 49 shared prompts
Spec	Claude Opus 4	GPT-5 Codex
Input price	$15/M tokens	—
Output price	$75/M tokens	—
Context window	200K tokens	—
Weights	Closed	—
Free API (OpenRouter)	No	No
Released	May 2025	Sep 2025
SWE-bench Verified	72.5%	74.5%