OpenAI Codex Mini vs 
Gemini 3.1 Flash Lite
Gemini 3.1 Flash Lite is cheaper than OpenAI Codex Mini at $0.25/M vs $1.5/M input tokens.
Pokémon Battle UI Recreation
Pokémon battle screen you can actually click. One HTML file.
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Which answer wins?
Written rounds
2 promptsFive jokes on demand, then count how many were actually different.
OpenAI Codex Mini: 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.
Gemini 3.1 Flash Lite: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything! What do you call a fake noodle? An impasta. Why did the scarecrow win an award? Because he was outstanding in his field. How does a penguin build its house? Igloo it together. What do you call a bear with no teeth? A gummy bear.
Three minutes of stand-up. Puns are banned.
OpenAI Codex Mini: [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.
Gemini 3.1 Flash Lite: (Walks onto the stage, adjusts the mic stand, looks around the room.) So, I recently turned thirty. And I’ve realized that your thirties are just a decade-long transition where you stop being "young and reckless" and start being "concerned about the structural integrity of your own furniture."
Price and specs
| Spec | OpenAI Codex Mini | Gemini 3.1 Flash Lite |
|---|---|---|
| Input price | $1.5/M tokens | $0.25/M tokens |
| Output price | $6/M tokens | $1.5/M tokens |
| Context window | 200K tokens | 1.0M tokens |
| Weights | — | Closed |
| Free API (OpenRouter) | No | No |
| Released | May 2025 | May 2026 |
| At 10M a month | $15.00 | $2.50 |
Input tokens at list price. No caching, no batch discount.
Where to run it
OpenAI Codex Mini
No hosts listed on OpenRouter.
Gemini 3.1 Flash Lite2 hosts
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Common questions
What is the difference between OpenAI Codex Mini and Gemini 3.1 Flash Lite?
OpenAI Codex Mini is developed by OpenAI while Gemini 3.1 Flash Lite is developed by Google AI. OpenAI Codex Mini has a 200K token context window vs Gemini 3.1 Flash Lite's 1.0M. You can compare their actual outputs across 10 challenges on Rival to see how they differ in practice.
Which is better, OpenAI Codex Mini or Gemini 3.1 Flash Lite?
It depends on your use case. OpenAI Codex Mini and Gemini 3.1 Flash Lite 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.
How much does OpenAI Codex Mini cost compared to Gemini 3.1 Flash Lite?
OpenAI Codex Mini costs $1.5/M input tokens and Gemini 3.1 Flash Lite costs $0.25/M input tokens. Gemini 3.1 Flash Lite is $1.25/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 OpenAI Codex Mini and Gemini 3.1 Flash Lite on Rival?
This page shows a side-by-side comparison of OpenAI Codex Mini and Gemini 3.1 Flash Lite 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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