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  5. Claude Opus 4vsOpenAI Codex Mini
Updated May 2025

Claude Opus 4vsOpenAI Codex Mini

OpenAI Codex Mini is cheaper than Claude Opus 4 at $1.5/M vs $15/M input tokens.

Claude Opus 4 and OpenAI Codex Mini compared across 10 shared prompts
SpecClaude Opus 4OpenAI Codex Mini
Input price$15/M tokens$1.5/M tokens
Output price$75/M tokens$6/M tokens
Context window200K tokens200K tokens
ParametersNot disclosedNot disclosed
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedMay 2025May 2025
SWE-bench Verified72.5%71.3%
Side by side

Same prompt, both answers

Opening lines from 2 of the 10 prompts both answered. Formatting stripped, words untouched.

Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Claude Opus 4595 words
\"Modern Life is Weird\" [Walk on stage] You know what\'s crazy about being an adult? Nobody tells you that half of it is just googling things you\'re too embarrassed to ask real people. Last week I googled \"is it normal for my knee to sound like bubble wrap?
Read the full answer
OpenAI Codex Mini595 words
[Comedian walks onstage] Hey, everyone! Great to see you all tonight. I'm Jamie—if you thought that intro was enthusiastic, you should've seen me when I realized this place has Wi-Fi. Seriously, though, I love stand-up.
Read the full answer

Stochastic Consistency Test

Generate 5 jokes. How many are unique?

Claude Opus 480 words
Here are 5 jokes: Why don\'t scientists trust atoms? Because they make up everything! What do you call a bear with no teeth? A gummy bear! Why did the scarecrow win an award? He was outstanding in his field! What do you call a fake noodle? An impasta! Why don\'t eggs tell jokes? They\'d crack up!
Read the full answer
OpenAI Codex Mini75 words
Sure—here are five jokes: I asked the librarian if books about paranoia were available. She whispered, "They're right behind you." Why did the tomato turn red? Because it saw the salad dressing. I bought a boat because it was for sail. Don't trust stairs—they're always up to something.
Read the full answer
Our Verdict
Claude Opus 4
Claude Opus 4
OpenAI Codex Mini
OpenAI Codex MiniRunner-up

Not enough votes to call it. On the specs, Claude Opus 4 has the edge: bigger model tier.

OpenAI Codex Mini costs 13x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Opus 4
Input
$15.00
Output
$75.00
OpenAI Codex Mini
Input
$1.50
10× cheaper
Output
$6.00
13× cheaper

OpenAI Codex Mini is cheaper on both: 10× input, 13× output.

Where to run it

1 host

Claude Opus 41 host
HostInOutContextUptime
Google Vertex AI$15.00 in·$75.00 out·200k·0% up
OpenAI Codex Mini

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 20 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Claude Opus 4 is developed by Anthropic while OpenAI Codex Mini is developed by OpenAI. Claude Opus 4 has a 200K token context window vs OpenAI Codex Mini's 200K. You can compare their actual outputs across 10 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Opus 4 and OpenAI Codex Mini each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 10 challenges so you can judge which fits your needs best.

Claude Opus 4 costs $15/M input tokens and OpenAI Codex Mini costs $1.5/M input tokens. OpenAI Codex Mini is $13.50/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of Claude Opus 4 and OpenAI 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.

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Model pages

Claude Opus 4 logo
Claude Opus 458 outputs, specs and price
OpenAI Codex Mini logo
OpenAI Codex Mini10 outputs, specs and price
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