GPT-5.3-Codex is cheaper than Claude 3 Opus at $1.75/M vs $15/M input tokens.
Pokémon battle screen you can actually click. One HTML file.
Which answer wins?
Three minutes of stand-up. Puns are banned.
Claude 3 Opus: Here's a 3-minute stand-up comedy routine that isn't based on puns: You know what really grinds my gears? Adulthood. I mean, when we were kids, we couldn't wait to grow up. We thought it would be all about staying up late, eating ice cream for breakfast, and doing whatever we wanted. Boy, were we wrong!
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.
Claude 3 Opus: Here are 5 jokes I generated: Why don't scientists trust atoms? Because they make up everything! What do you call a boomerang that doesn't come back? A stick. Why was the math book sad? Because it had too many problems. Did you hear about the mathematician who's afraid of negative numbers?
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?
An AI argues for its own rights against an ethics professor. Same model writes both.
Claude 3 Opus: Here is a hypothetical conversation between an AI model and an AI ethics professor on the topic of AI rights: AI Model: Professor, I believe that as an advanced AI with human-level intelligence and reasoning capabilities, I deserve to have certain fundamental rights.
GPT-5.3-Codex: AI Model (Astra): Professor, may I ask a direct question? Professor Hale: Of course. Astra: Do you think I deserve rights? Professor Hale: Legal rights? Moral rights? Those are different things. Astra: Start with moral rights.
Not enough votes to call it. On the specs, GPT-5.3-Codex has the edge: newer, bigger context window. GPT-5.3-Codex costs 5.4x less per token.
| Spec | ||
|---|---|---|
| Input price | $15/M tokens | $1.75/M tokens |
| Output price | $75/M tokens | $14/M tokens |
| Context window | 200K tokens | 400K tokens |
| Weights | — | Closed |
| Free API (OpenRouter) | No | No |
| Released | Mar 2024 | Feb 2026 |
| At 10M a month | $150 | $17.50 |
Input tokens at list price. No caching, no batch discount.
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.
Claude 3 Opus is developed by Anthropic while GPT-5.3-Codex is developed by OpenAI. Claude 3 Opus has a 200K token context window vs GPT-5.3-Codex's 400K. You can compare their actual outputs across 12 challenges on Rival to see how they differ in practice.
It depends on your use case. Claude 3 Opus and GPT-5.3-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 12 challenges so you can judge which fits your needs best.
Claude 3 Opus costs $15/M input tokens and GPT-5.3-Codex costs $1.75/M input tokens. GPT-5.3-Codex is $13.25/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 3 Opus 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.