Gemini 2.5 Flash Preview 05-20 vs 
GPT-5.3-Codex
Gemini 2.5 Flash Preview 05-20 is cheaper than GPT-5.3-Codex at $0.15/M vs $1.75/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 promptsThree minutes of stand-up. Puns are banned.
Gemini 2.5 Flash Preview 05-20: Alright, alright, settle down you magnificent collection of human beings! You look good tonight. Not just good, but… like you've all collectively decided to nail the 'I'm here to laugh and avoid talking about my Monday' look. And I respect that. Seriously though, it's great to be back on stage. I'm living the dream.
GPT-5.3-Codex: Good evening, everybody! I’ve reached that age where my body sends me passive-aggressive emails. Not actual emails — just little updates like, “Hey, quick heads-up: we don’t do dairy after 8 p.m. anymore.” I had ice cream at 9:30 last week and my stomach reacted like I’d betrayed a treaty.
Five jokes on demand, then count how many were actually different.
Gemini 2.5 Flash Preview 05-20: Here are 5 jokes for you: 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! I told my wife she was drawing her eyebrows too high. She looked surprised.
GPT-5.3-Codex: Sure—here are 5 jokes: Why don’t skeletons fight each other? They don’t have the guts. I told my computer I needed a break… Now it won’t stop sending me KitKat ads. Why did the math book look sad? It had too many problems. I used to play piano by ear… Now I use my hands. Why did the scarecrow win an award?
Price and specs
Not enough votes to call it. On the specs, GPT-5.3-Codex has the edge: bigger model tier, newer. Gemini 2.5 Flash Preview 05-20 costs 23x less per token.
| Spec | Gemini 2.5 Flash Preview 05-20 | GPT-5.3-Codex |
|---|---|---|
| Input price | $0.15/M tokens | $1.75/M tokens |
| Output price | $0.6/M tokens | $14/M tokens |
| Context window | 1.0M tokens | 400K tokens |
| Weights | — | Closed |
| Free API (OpenRouter) | No | No |
| Released | May 2025 | Feb 2026 |
| At 10M a month | $1.50 | $17.50 |
Input tokens at list price. No caching, no batch discount.
Where to run it
Gemini 2.5 Flash Preview 05-20
No hosts listed on OpenRouter.
GPT-5.3-Codex2 hosts
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Common questions
What is the difference between Gemini 2.5 Flash Preview 05-20 and GPT-5.3-Codex?
Gemini 2.5 Flash Preview 05-20 is developed by Google AI while GPT-5.3-Codex is developed by OpenAI. Gemini 2.5 Flash Preview 05-20 has a 1.0M token context window vs GPT-5.3-Codex's 400K. You can compare their actual outputs across 11 challenges on Rival to see how they differ in practice.
Which is better, Gemini 2.5 Flash Preview 05-20 or GPT-5.3-Codex?
It depends on your use case. Gemini 2.5 Flash Preview 05-20 and GPT-5.3-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 11 challenges so you can judge which fits your needs best.
How much does Gemini 2.5 Flash Preview 05-20 cost compared to GPT-5.3-Codex?
Gemini 2.5 Flash Preview 05-20 costs $0.15/M input tokens and GPT-5.3-Codex costs $1.75/M input tokens. Gemini 2.5 Flash Preview 05-20 is $1.60/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 Gemini 2.5 Flash Preview 05-20 and GPT-5.3-Codex on Rival?
This page shows a side-by-side comparison of Gemini 2.5 Flash Preview 05-20 and GPT-5.3-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.
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