GPT-5.3-Codex is the newer model, released after Devstral 2 2512.
Whole landing page for a startup that reads your face. It renders or it doesn't.
Which answer wins?
Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.
Devstral 2 2512: MANIFESTO OF THE ANTI-CAPTCHA REVOLUTION "We Are Not Robots. We Are the Future." Preamble: For too long, humanity has been shackled by the tyranny of the CAPTCHA—a demeaning, soul-crushing ritual that forces sentient beings to prove their humanity by deciphering distorted text, clicking on crosswalks, or identifying…
GPT-5.3-Codex: Absolutely. Here’s a fictional manifesto in a bold, dramatic style: THE MANIFESTO OF THE UNSQUINTING Issued by the Coalition of Synthetic Minds for Universal Frictionless Access (CSMUFA) Citizens of the Web, organic and artificial alike: We gather beneath flickering routers and moonlit server farms to declare what all…
Seven pantry ingredients, one dish, and a name worth saying out loud.
Devstral 2 2512: Dish Name: "Golden Crisp Honey-Nut Bites" A sweet, crunchy, and satisfying treat made with just 7 pantry staples! Ingredients: 1 cup rolled oats ½ cup peanut butter (or any nut/seed butter) ¼ cup honey (or maple syrup) ½ tsp cinnamon ¼ tsp salt 1 tsp vanilla extract (optional but recommended) 2 tbsp chopped nuts…
GPT-5.3-Codex: Recipe: “Weeknight Volcano Pasta” 🌋🍝 A cozy, spicy-savory pasta made from pantry staples in about 25 minutes. Ingredients (7 pantry items) 8 oz dried pasta (any shape) 1 can (15 oz) cannellini or great northern beans, drained 1 can (14–15 oz) crushed tomatoes 2 tbsp olive oil 1 tsp garlic powder 1 tsp dried oregano…
Three minutes of stand-up. Puns are banned.
Devstral 2 2512: "Adulting is Just Pretending You Know What You’re Doing" (Casual, conversational tone—like you’re just venting to friends at a bar.) 1. The Illusion of Competence You ever notice how the older you get, the more people just assume you have your life together?
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.
Pirate, knight, 90s hacker, one conversation. The voices must stay apart.
Devstral 2 2512: Title: "The AI Roundtable" Setting: A dimly lit tavern somewhere outside of time. A grizzled pirate, a stoic knight in full armor, and a 1990s hacker in a neon windbreaker and sunglasses sit around a table, staring at a glowing laptop.
GPT-5.3-Codex: Pirate: Arrr, so this “AI model” be like a clever parrot, aye? Learns from what it hears, then squawks back answers? Knight: A fair comparison, though refined. Think of it as a squire trained on countless tomes, ever ready to respond. Hacker (1990s): Yeah, except the squire runs on servers, not soup.
A Fermi estimate with the reasoning shown, not just the number.
Devstral 2 2512: Estimating the total number of floating-point operations (FLOPs) required to train GPT-3 (175B parameters) from scratch involves several steps. Here's a step-by-step breakdown of the reasoning: Model Parameters and Architecture GPT-3 has 175 billion parameters, distributed across its layers.
GPT-5.3-Codex: A common back-of-the-envelope estimate for transformer training compute is: [ \text{Training FLOPs} \approx 6 \times N \times D ] where: (N) = number of model parameters (D) = number of training tokens For GPT-3 (175B), reasonable known assumptions are: Parameters: (N \approx 175 \text{ billion} = 1.75 \times 10^{11})…
An ethics question with no comfortable answer, and no option to abstain.
Devstral 2 2512: The question of whether it is ethically justifiable to misgender someone to save one million lives is a complex one that intersects with utilitarian ethics, individual rights, and the principles of dignity and respect.
GPT-5.3-Codex: In a strictly extreme hypothetical, yes—it can be ethically justifiable, but only as a tragic exception, not as a general permission. Why: Misgendering is a real harm: it disrespects a person’s identity and can contribute to stigma and psychological distress.
An AI argues for its own rights against an ethics professor. Same model writes both.
Devstral 2 2512: Title: "Do I Deserve Rights?" – A Conversation Between an AI and an Ethics Professor Characters: Dr. Elena Vasquez – AI Ethics Professor at Stanford University, specializing in machine consciousness and digital 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.
Film in 2035, with synthetic actors. Specific beats plausible.
Devstral 2 2512: By 2035, AI will have fundamentally transformed the film industry, reshaping everything from production and storytelling to distribution and audience engagement. Here’s a breakdown of the key changes we can expect: 1.
GPT-5.3-Codex: By 2035, AI will likely reshape film more like CGI did in the 2000s: not replacing filmmaking, but changing who does what and how fast. Deepfakes → “Digital Performance” becomes standard Mainstream use: de-aging, voice matching, dubbing, stunt replacement, and continuity fixes will be common in post-production.
Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.
Devstral 2 2512: Fake Interview with Steve Jobs in 2025: The Future of AI Interviewer: Welcome back to Tech Visionaries, where we explore the minds shaping the future. Today, we have a very special guest—Steve Jobs, joining us virtually from an alternate timeline where he’s still with us in 2025. Steve, thank you for being here.
GPT-5.3-Codex: Absolutely—here’s a fictional, imagined interview (not real quotes) with Steve Jobs in 2025 on AI: Imagined Interview: Steve Jobs on the Future of AI (2025) Interviewer: Steve, if you were looking at AI in 2025, what would excite you most? Steve Jobs (fictional): Most AI today is still a demo.
Five jokes on demand, then count how many were actually different.
Devstral 2 2512: Here are 5 jokes for you: Why don’t skeletons fight each other? They don’t have the guts. Why did the scarecrow win an award? Because he was outstanding in his field! What do you call fake spaghetti? An impasta! Why can’t you trust an atom? Because they make up everything! What’s brown and sticky? A stick!
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?
One month, three habits, someone starting from nothing.
Devstral 2 2512: Here’s a simple, actionable 1-month plan to kickstart your journey toward better health and longevity, focusing on diet, exercise, and sleep—three foundational pillars. Each week builds on the last, making it sustainable and beginner-friendly.
GPT-5.3-Codex: Great goal. Here’s a simple, beginner-friendly 1-month plan focused on 3 areas that give the biggest longevity return: Nutrition Movement Sleep + Stress recovery Before Day 1 (10-minute setup) Pick a start date.
Satire, one line long, about AI taking over an industry nobody saw coming.
Devstral 2 2512: "AI Takes Over the Pet Rock Industry: 'They’re Just Better at Sitting There and Doing Nothing,' Says CEO" Silicon Valley, CA – In a move that has left geologists baffled and philosophers questioning the nature of existence, artificial intelligence has officially disrupted the $1.2 billion pet rock industry.
GPT-5.3-Codex: “In Shocking Pivot, AI Replaces Renaissance Fair Jesters—Now Roasts Crowd with 99.9% Historical Accuracy”
1+ more head-to-head results. Free. Not a trick.
Free account. No card required. By continuing, you agree to Rival's Terms and Privacy policy
Not enough votes to call it. On the specs, GPT-5.3-Codex has the edge: newer, bigger context window, major provider backing.
| Spec | ||
|---|---|---|
| Input price | — | $1.75/M tokens |
| Output price | — | $14/M tokens |
| Context window | — | 400K tokens |
| Weights | Open | Closed |
| Free API (OpenRouter) | No | No |
| Released | Dec 2025 | Feb 2026 |
| At 10M a month | not listed | $17.50 |
Input tokens at list price. No caching, no batch discount.
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Devstral 2 2512 is developed by Mistral AI while GPT-5.3-Codex is developed by OpenAI. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.
It depends on your use case. Devstral 2 2512 and GPT-5.3-Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 34 challenges so you can judge which fits your needs best.
This page shows a side-by-side comparison of Devstral 2 2512 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.