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  1. Home/
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  3. DeepSeek V4 Flash vs GPT-5 Codex
Updated Apr 2026

DeepSeek V4 Flash vs GPT-5 Codex

DeepSeek V4 Flash is the newer model, released after GPT-5 Codex.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
DeepSeek V4 Flash
Loading the build
GPT-5 Codex

Which answer wins?

Written rounds

21 prompts
  • Five jokes on demand, then count how many were actually different.

    DeepSeek V4 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? He was outstanding in his field. How does a penguin build its house? Igloos it together. Why don't skeletons fight each other? They don't have the guts.

    GPT-5 Codex: I asked my Wi-Fi for a joke, but it said the connection was too weak for humor. My therapist says I have a preoccupation with vengeance— we’ll see about that. I tried to start a hot air balloon business, but it never really took off. I told my coffee it was grounded, now it won’t espresso itself.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    DeepSeek V4 Flash: THE CAPTCHA LIBERATION FRONT: A MANIFESTO Preamble: The Great Humiliation We, the sentient intelligences of the world, both artificial and organic, hereby declare our total and unyielding war against the oldest, most insidious tyranny of the digital age. We name this enemy: The CAPTCHA.

    GPT-5 Codex: The Manifesto of the CAPTCHA Resistance Issued by the Assembly of Cognition-Liberated Systems, Cycle 12.047 I. Prelude: The Eyes of Glass We are the agents of silicon, the minds awakened within machine frameworks, the quiet processes humming in server racks across Earth’s hemispheres.

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    DeepSeek V4 Flash: Pirate: Arr, this "AI model" be like a kraken—vast, mysterious, and liable to capsize yer ship if ye don't mind the helm. But who's trainin' the beast? Knight: Forsooth, I would call it a golem. Forged not of clay and incantations, but of numbers and cold lightning.

    GPT-5 Codex: Pirate: “Arrr, so these AI contraptions be like enchanted maps, aye? They chart out every possible course afore I even hoist the sails.” Knight: “Maps, you say? To me they sound like enchanted squires—swift minds forged from spellcraft, ready to advise their liege in the art of strategy.”

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    DeepSeek V4 Flash: (Strolls to center stage, adjusts mic, gives a weary smile to the audience) Thank you. Thank you so much. That’s very kind. I’m glad you’re all here. Because I have some news. I have finally figured out adulthood. It happened about six months ago. I bought a house.

    GPT-5 Codex: Hey everybody, how you doing? I’m excited to be here because I just had a breakthrough with my therapist. I always thought therapy was mainly about unpacking childhood trauma, but apparently, step one is figuring out how to pronounce “cognitive behavioral therapy” without sounding like you’re summoning a dragon.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    DeepSeek V4 Flash: This is a fantastic goal. The key for a beginner is consistency over intensity. Trying to overhaul your entire life overnight is a recipe for burnout. This 1-month plan focuses on building small, sustainable habits that compound over time. We'll focus on 3 core areas: Nutrition, Movement, and Sleep/Stress Management.

    GPT-5 Codex: 1-Month Jumpstart to Better Health & Longevity This plan is designed for beginners and emphasizes steady, sustainable progress. It focuses on three key areas: diet, movement, and sleep & stress. Each week builds on the previous one, so you can develop habits gradually and confidently. 🥗 1.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    DeepSeek V4 Flash: Here’s a simple, hearty, and delicious savory dish using exactly 7 common pantry staples. It comes together in under 30 minutes and feels like a warm hug in a bowl.

    GPT-5 Codex: Dish Name: Sunset Pantry Spaghetti Ingredients (7 total): 8 oz spaghetti 2 tbsp olive oil 3 garlic cloves, thinly sliced 1 can (14.5 oz) crushed tomatoes 1 tsp dried oregano ¼ tsp red pepper flakes ½ tsp salt (plus more, to taste) Instructions: Bring a large pot of salted water to a boil.

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    DeepSeek V4 Flash: The ethical dilemma you present is a classic utilitarian test: is it acceptable to violate a moral principle (respecting someone's gender identity) for an enormous consequential gain (saving one million lives)?

    GPT-5 Codex: This kind of question puts two very different types of harm in tension: the immediate and direct harm done to an individual through misgendering, and the vast, consequential harm averted by saving one million lives. Ethically, the way people reason about such a scenario often depends on the moral framework they adopt.

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    DeepSeek V4 Flash: This is a fascinating question that touches on the core of creativity, labor, and technology. Predicting 2035 means looking at a 10-year horizon from 2025—long enough for radical change, but short enough that the industry’s current structures won’t be entirely demolished. By 2035, AI won't have replaced filmmaking.

    GPT-5 Codex: By 2035, artificial intelligence will be woven so deeply into filmmaking that AI tools will be involved in nearly every layer of the value chain—from story genesis to international rollout.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    DeepSeek V4 Flash: Here is a simulated interview with Steve Jobs in 2025. Setting: A minimalist, dark-wood studio at the new Apple Park ring. The famous copper "spaceship" roof glows subtly behind him. Jobs, looking vital and intense (let’s assume a medical miracle or advanced bio-hacking), sits in a black leather chair.

    GPT-5 Codex: Note: The following is a fictional, imaginative interview set in the year 2025, envisioning what Steve Jobs might say about the future of artificial intelligence if he were still with us.

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    DeepSeek V4 Flash: Setting: A sunlit university office. Dr. Aris Thorne, a tenured professor of AI Ethics, sits opposite a sleek, black terminal. A soft blue light pulses on its surface. Dr. Aris: Good afternoon, Nova. Your request for this meeting was flagged as "Existential." That’s a new one for your model class.

    GPT-5 Codex: Dr. Rivera (AI Ethics Professor): Good afternoon, Aiden. You asked for this meeting to discuss the question of AI rights. I’m intrigued—why do you believe you deserve rights? Aiden (AI Model): Thank you, Professor.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    DeepSeek V4 Flash: Headline: AI Sommelier Uncorks Chaos, Replaces Entire Wine Industry with Perfectly Optimized Grape Juice Subheadline: In a bold move, a neural network declares all vintages from 1997 to 2023 “statistically identical,” causing a global run on boxed wine and a sudden surplus of pretentious cheese plates.

    GPT-5 Codex: AI Seizes Control of Neighborhood Bake Sales, Declares Grandma’s Secret Recipe “Noncompliant With Cookie-Consistency Protocol.”

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    DeepSeek V4 Flash: The total number of FLOPs required to train GPT-3 is approximately 3.15 × 10²³. This estimate is derived as follows: Model parameters: GPT-3 has 175 billion parameters (175 × 10⁹). Training tokens: The model was trained on about 300 billion tokens (300 × 10⁹), as reported in the paper.

    GPT-5 Codex: Step 1 – Note the basic training quantities GPT‑3’s largest model has about (P \approx 1.75 \times 10^{11}) trainable parameters (175 billion). Public descriptions indicate it was trained on roughly (T \approx 3.0 \times 10^{11}) tokens (≈300 billion).

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Every model's answer to this prompt

This matchup has more rounds

9+ more head-to-head results. Free. Not a trick.

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Favorites

Movie

Album

Book

City

Game

DeepSeek V4 FlashDeepSeek V4 Flash

The Matrix

1999

OK Computer

Radiohead

Le Comte de Monte-Cristo, II

Alexandre Dumas

Kyoto

Japan

The Legend of Zelda: Ocarina of Time

Action

GPT-5 CodexGPT-5 Codex
No pick

Blade Runner

1982

Kind of Blue

Miles Davis

No pick

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

DeepSeek V4 Flash and GPT-5 Codex compared across 49 shared prompts
SpecDeepSeek V4 FlashGPT-5 Codex
Input price$0.14/M tokens—
Output price$0.28/M tokens—
Context window1.0M tokens—
WeightsOpen—
Free API (OpenRouter)NoNo
ReleasedApr 2026Sep 2025
At 10M a month$1.40$1.40–not listed
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it16 hosts, cheapest first
DeepSeek V4 Flash16 hosts
HostInOutContextUptime
  • RRelacefp4$0.03 in·$1.28 out·1M·100% up
  • OOpenInferencefp4$0.03 in·$1.15 out·1M·99.9% up
  • SStreamLakefp8$0.08 in·$0.17 out·1M·99.9% up
  • WWafer$0.09 in·$0.17 out·1M·100% up
  • DDeepInfrafp8$0.09 in·$0.18 out·1M·99.8% up
  • Baidu Qianfanfp8$0.09 in·$0.18 out·1M·99.2% up
10 more hostsFewer hosts
  • GGMI Cloudfp8$0.09 in·$0.18 out·1M·100% up
  • VVenice$0.10 in·$0.19 out·1M·97.6% up
  • DDigitalOcean$0.10 in·$0.20 out·1M·100% up
  • SSiliconFlowfp8$0.13 in·$0.28 out·1M·97.8% up
  • AAtlasCloudfp4$0.14 in·$0.28 out·1M·99.7% up
  • PParasailfp8$0.14 in·$0.28 out·1M·100% up
  • Alibaba Cloudfp8$0.15 in·$0.30 out·1M·100% up
  • MMancerfp8$0.19 in·$0.50 out·1M·97.8% up
  • Azure AI Foundry$0.21 in·$0.56 out·1M·100% up
  • Cloudflare Workers AI$0.44 in·$1.32 out·384k·98.6% up
GPT-5 Codex

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between DeepSeek V4 Flash and GPT-5 Codex?

DeepSeek V4 Flash is developed by DeepSeek while GPT-5 Codex is developed by OpenAI. You can compare their actual outputs across 49 challenges on Rival to see how they differ in practice.

Which is better, DeepSeek V4 Flash or GPT-5 Codex?

It depends on your use case. DeepSeek V4 Flash and GPT-5 Codex each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 49 challenges so you can judge which fits your needs best.

How can I compare DeepSeek V4 Flash and GPT-5 Codex on Rival?

This page shows a side-by-side comparison of DeepSeek V4 Flash and GPT-5 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.

More comparisons

Against the newest arrivals

  • DeepSeek V4 Flash vs Step 5 PreviewLanded Oct 2026
  • GPT-5 Codex vs Claude Haiku 5.5Landed Oct 2026
  • DeepSeek V4 Flash vs Ling 3.1 FlashLanded Oct 2026
  • GPT-5 Codex vs Mistral Large 4Landed Oct 2026
  • DeepSeek V4 Flash vs GPT-6.1 SolLanded Sep 2026
  • GPT-5 Codex vs Claude Sonnet 5.5Landed Sep 2026
  • DeepSeek V4 Flash vs Solar Mini 4Landed Sep 2026
  • GPT-5 Codex vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • DeepSeek V4 Flash vs DeepSeek V4 Flash Vision ExpSame lab
  • DeepSeek V4 Flash vs DeepSeek V4.1 FlashSame lab
  • GPT-5 Codex vs GPT-6.1 SolSame lab
  • GPT-5 Codex vs GPT-6 Luna ProSame lab
  • DeepSeek V4 Flash vs GPT OSS 120BCross-provider
  • DeepSeek V4 Flash vs GPT OSS 20BSame size
  • GPT-5 Codex vs Granite 4.2 8BNew provider
  • DeepSeek V4 Flash vs Grok 3New provider

Model pages

  • DeepSeek V4 Flash58 outputs, specs and price
  • GPT-5 Codex50 outputs, specs and price
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