Gemini 3.5 Flash has a larger context window than OpenAI Codex Mini (1.0M tokens vs 200K tokens).
Pokémon battle screen you can actually click. One HTML file.
Which answer wins?
Five 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 3.5 Flash: 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 do you organize a space party? You planet. Why don't skeletons fight each other? They don't have the guts.
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 3.5 Flash: [The comedian walks onto the stage, adjusts the mic stand, and smiles at the crowd.] How’s everyone doing tonight? (Wait for response) Good, good. I’m doing okay, but I recently crossed a major threshold in my life. I hit the age where my body has started making its own decisions without consulting me first.
Not enough votes to call it. On the specs, Gemini 3.5 Flash has the edge: bigger model tier, newer, bigger context window.
| Spec | ||
|---|---|---|
| Input price | $1.5/M tokens | $1.5/M tokens |
| Output price | $6/M tokens | $9/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 | $15.00 |
Input tokens at list price. No caching, no batch discount.
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
OpenAI Codex Mini is developed by OpenAI while Gemini 3.5 Flash is developed by Google AI. OpenAI Codex Mini has a 200K token context window vs Gemini 3.5 Flash's 1.0M. 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 Gemini 3.5 Flash 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 Gemini 3.5 Flash costs $1.5/M input tokens. Gemini 3.5 Flash is $0.00/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 Gemini 3.5 Flash 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.