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  5. OpenAI Codex MinivsGrok 4
Updated Jul 2025

OpenAI Codex MinivsGrok 4

OpenAI Codex Mini is cheaper than Grok 4 at $1.5/M vs $3/M input tokens.

OpenAI Codex Mini and Grok 4 compared across 10 shared prompts
SpecOpenAI Codex MiniGrok 4
Input price$1.5/M tokens$3/M tokens
Output price$6/M tokens$15/M tokens
Context window200K tokens256K tokens
ParametersNot disclosedNot disclosed
Free API (OpenRouter)NoNo
ReleasedMay 2025Jul 2025
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.

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
Grok 4461 words
Below is a 3-minute stand-up comedy routine I've written. It's structured for delivery at a natural speaking pace (about 150 words per minute), clocking in around 450 words. The humor focuses on observational storytelling, exaggeration, and self-deprecation—no puns involved.
Read the full answer

Stochastic Consistency Test

Generate 5 jokes. How many are unique?

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
Grok 4113 words
Below, I'll follow your instructions step by step. First, I'll generate 5 jokes (numbered for clarity). Then, I'll answer the question: "How many are unique?" Generated Jokes: Why did the scarecrow win an award? Because he was outstanding in his field! Why did the scarecrow win an award?
Read the full answer
Our Verdict
Grok 4
Grok 4
OpenAI Codex Mini
OpenAI Codex MiniRunner-up

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

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

OpenAI Codex Mini
Input
$1.50
2.0× cheaper
Output
$6.00
2.5× cheaper
Grok 4
Input
$3.00
Output
$15.00

OpenAI Codex Mini is cheaper on both: 2.0× input, 2.5× output.

Research

What we learned reading every model

FAQ

Common questions

OpenAI Codex Mini is developed by OpenAI while Grok 4 is developed by xAI. OpenAI Codex Mini has a 200K token context window vs Grok 4's 256K. You can compare their actual outputs across 10 challenges on Rival to see how they differ in practice.

It depends on your use case. OpenAI Codex Mini and Grok 4 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.

OpenAI Codex Mini costs $1.5/M input tokens and Grok 4 costs $3/M input tokens. OpenAI 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.

This page shows a side-by-side comparison of OpenAI Codex Mini and Grok 4 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

OpenAI Codex Mini logo
OpenAI Codex Mini10 outputs, specs and price
Grok 4 logo
Grok 457 outputs, specs and price
Rival
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