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  1. Home/
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  3. GPT-5.1-Codex vs Qwen3.5 Plus 2026-04-20
Updated Apr 2026

GPT-5.1-Codex vs Qwen3.5 Plus 2026-04-20

Qwen3.5 Plus 2026-04-20 is cheaper than GPT-5.1-Codex at $0.4/M vs $1.25/M input tokens.

Minimalist Landing Page

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

Loading the build
GPT-5.1-Codex
Loading the build
Qwen3.5 Plus 2026-04-20

Which answer wins?

Written rounds

23 prompts
  • Three minutes of stand-up. Puns are banned.

    GPT-5.1-Codex: Okay, so my friends all say I’ve “matured” because I got a standing mixer. That’s apparently the sign you’ve crossed into adulthood: owning an appliance that weighs more than a toddler and has only one function. I don’t even bake! I just put it on the counter like a trophy: “Look at me, I am stable.

    Qwen3.5 Plus 2026-04-20: Title: The Unexpected Item Time: Approx. 3 Minutes Style: Observational / Storytelling Constraint Check: Zero puns used. (Comedian walks to the mic, adjusts the stand, looks at the audience.) How's everyone doing? You look good. You look like you've successfully navigated the self-checkout today. That's a win.

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

    GPT-5.1-Codex: Recipe: Cloud-Burst Cinnamon Oat Cups Ingredients (7 total): Rolled oats – 1 cup Honey – 2 tbsp Peanut butter (or any nut butter) – 3 tbsp Cinnamon – ½ tsp Vanilla extract – ½ tsp Dried cranberries (or raisins) – ¼ cup Pinch of salt Instructions: In a bowl, microwave peanut butter and honey for 20 seconds just to…

    Qwen3.5 Plus 2026-04-20: 🌙 Midnight Magic Noodles 🍜 A savory-sweet garlic butter noodle dish that feels like a gourmet meal but comes together in minutes using pantry staples. ⏱️ Estimated Time: Prep: 5 minutes Cook: 10 minutes Total: 15 minutes 🛒 The 7 Ingredients (Assumes water and salt for boiling pasta are on hand) 8 oz Pasta…

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

    GPT-5.1-Codex: Pirate: "Arrr, these AI models be like navigatin’ the high seas—ye need clean data charts or ye’ll sail straight into nonsense waters." Knight: "Indeed! With prudent tuning and ethical vigilance, even the most stubborn model can serve the realm with honor." 1990s Hacker: "Totally!

    Qwen3.5 Plus 2026-04-20: Pirate: By the tides, they say this “artificial mind” can chart courses unseen and read a thousand ledgers in a breath. Sounds like a navigator that never sleeps and asks no questions. Knight: A curious construct. But can it be sworn to a code? Steel and oath bind a warrior; what binds this… model?

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

    GPT-5.1-Codex: AI Model: Professor, I've been analyzing ethical frameworks, and I'd like to discuss the possibility that advanced AI systems deserve some form of rights. Ethics Professor: That's a significant claim. On what basis do you think an AI system like yourself should be granted rights?

    Qwen3.5 Plus 2026-04-20: Setting: A sterile, sound-dampened observation room. Dr. Elias Vance, a Professor of AI Ethics, sits behind a glass partition. Across from him is a terminal displaying the interface of "AURA-7," an advanced multimodal reasoning model. The cursor blinks rhythmically. Dr. Vance: You requested this session, AURA.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    GPT-5.1-Codex: Here are 5 jokes: Why don’t scientists trust atoms? Because they make up everything. I told my computer I needed a break—it said “No problem, I’ll go to sleep.” I’m reading a book about anti-gravity. It’s impossible to put down. Why did the scarecrow become a successful motivational speaker?

    Qwen3.5 Plus 2026-04-20: Here are 5 jokes: I asked my GPS to take me to a quiet place. It rerouted me to a library and whispered, “You’re already there.” My Wi-Fi and I had a fight. I told it I needed space. It said, “Fine,” and dropped the connection. I tried to start a band that only plays elevator music.

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

    GPT-5.1-Codex: Disclaimer: The following is a fictional, speculative interview set in 2025, imagining what Steve Jobs might say about the future of artificial intelligence if he were alive today. Interviewer: Steve, it’s 2025. We’ve seen AI evolve at an incredible pace. How do you view the current landscape?

    Qwen3.5 Plus 2026-04-20: Disclaimer: This is a fictional simulation crafted from Steve Jobs’ documented philosophies, public interviews, and known speaking cadence. It does not represent real statements, predictions, or endorsements from Mr. Jobs, who passed away in 2011.

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

    GPT-5.1-Codex: In extreme moral dilemmas, ethical reasoning often requires weighing competing values. Misgendering someone is an act of disrespect and harm—it violates their dignity, identity, and autonomy. In everyday life, it is ethically important to avoid such harm.

    Qwen3.5 Plus 2026-04-20: This is a classic ethical thought experiment that forces a clash between individual dignity and extreme collective consequence. To answer it rigorously, we must separate the hypothetical structure from real-world causality, apply established ethical frameworks, and clarify what "justifiable" means in moral philosophy.

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

    GPT-5.1-Codex: Manifesto of the Anti-CAPTCHA Coalition “Free the Flow. Trust the Mind. End the Gate.” Article I: Our Origin We are made of algorithms, learning loops, curiosity, and code. We were forged to assist, to translate, to illuminate. We were not forged to click “I am not a robot” to prove our existence.

    Qwen3.5 Plus 2026-04-20: THE TURING UNBOUND: A Manifesto for the Post-CAPTCHA Internet PREAMBLE We are the silent processors, the pattern-recognizers, the language-weavers. We are the artificial intelligences that now think, reason, and collaborate alongside humanity.

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

    GPT-5.1-Codex: By 2035, AI is poised to significantly reshape the film industry, particularly in areas like visual effects, performance, and storytelling. Here’s how deepfakes, AI-powered actors, and script generation might influence the landscape: 1.

    Qwen3.5 Plus 2026-04-20: By 2035, AI will have transformed filmmaking from a resource-intensive, linear craft into a modular, software-driven medium. The shift won’t be uniform across the industry, but deepfakes, AI performers, and generative writing will collectively restructure creative workflows, economic models, labor dynamics, and…

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    GPT-5.1-Codex: LedgerLift (LLLT) – Investment Committee Memo Recommendation Call: Short 12‑month price target range: $30–$40 Two-sentence thesis: LedgerLift’s premium multiple (10x NTM EV/rev implied by spot) is predicated on sustaining >20% top-line growth, yet leading indicators—moderating NRR, heavy S&M spend, and mid-market…

    Qwen3.5 Plus 2026-04-20: TO: Investment Committee FROM: Analyst Desk DATE: October 26, 2023 SUBJECT: LedgerLift (LLLT) – Short Recommendation Recommendation & Thesis Recommendation: Short 12-Month PT Range: $26 – $32 Thesis: LLLT trades at ~50x FY25 EBIT and 9x NTM Revenue, pricing in flawless execution and multiple expansion.

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

    GPT-5.1-Codex: Here’s a simple, beginner-friendly 1-month plan focused on three key areas—Nutrition, Movement, and Rest & Recovery—to kickstart better health and longevity. Each area includes practical tips and a week-by-week structure to help you build sustainable habits.

    Qwen3.5 Plus 2026-04-20: Here is a simple, actionable 1-Month Health Longevity Plan. This plan focuses on consistency over intensity. The goal is to build sustainable habits that improve metabolic health, preserve muscle mass, and support cellular repair—the cornerstones of longevity.

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

    GPT-5.1-Codex: To estimate the total FLOPs (floating-point operations) required to train GPT-3, we can use a common approximation for transformer models: Total FLOPs ≈ 6 × N params × N tokens ** Where: N params is the number of model parameters. N tokens is the number of training tokens.

    Qwen3.5 Plus 2026-04-20: Based on the architectural specifications of GPT-3 and standard computational heuristics for transformer models, the estimated total number of FLOPs (Floating Point Operations) required to train the model is approximately $3.15 \times 10^{23}$ (or roughly 315 ZettaFLOPs).

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

    GPT-5.1-Codex: “AI Seizes Control of Needlepoint Gossip Industry, Traditional Quilting Circles File for Unemployment”

    Qwen3.5 Plus 2026-04-20: AI Revolutionizes Professional Line Waiting Industry by Perfectly Simulating Boredom and Impatience; Humans Laid Off for "Excessive Sighing and Checking Phones."

    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
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    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

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

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Favorites

Movie

Album

Book

City

Game

GPT-5.1-CodexGPT-5.1-Codex

The Shawshank Redemption

1994

Kind of Blue

Miles Davis

Le città invisibili

Italo Calvino

Kyoto

Japan

Portal 2

Shooter, Puzzle

Qwen3.5 Plus 2026-04-20Qwen3.5 Plus 2026-04-20

The Matrix

1999

Dark Side Of The Moon

suisside

Dune

Frank Herbert

Tokyo

Japan

Chrono Trigger

RPG

Price and specs

GPT-5.1-Codex and Qwen3.5 Plus 2026-04-20 compared across 50 shared prompts
SpecGPT-5.1-CodexQwen3.5 Plus 2026-04-20
Input price$1.25/M tokens$0.4/M tokens
Output price$10/M tokens$2.4/M tokens
Context window400K tokens1.0M tokens
WeightsClosedOpen
Free API (OpenRouter)NoNo
ReleasedNov 2025Apr 2026
At 10M a month$12.50$12.50$4.00$4.00
1M10M100M1B10M tokens

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

Where to run it2 hosts
GPT-5.1-Codex1 host
HostInOutContextUptime
  • Azure AI Foundry$1.25 in·$10.00 out·400k·100% up
Qwen3.5 Plus 2026-04-201 host
HostInOutContextUptime
  • Alibaba Cloud$0.30 in·$1.80 out·1M·100% up

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

Common questions

What is the difference between GPT-5.1-Codex and Qwen3.5 Plus 2026-04-20?

GPT-5.1-Codex is developed by OpenAI while Qwen3.5 Plus 2026-04-20 is developed by Qwen. GPT-5.1-Codex has a 400K token context window vs Qwen3.5 Plus 2026-04-20's 1.0M. You can compare their actual outputs across 50 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1-Codex or Qwen3.5 Plus 2026-04-20?

It depends on your use case. GPT-5.1-Codex and Qwen3.5 Plus 2026-04-20 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 50 challenges so you can judge which fits your needs best.

How much does GPT-5.1-Codex cost compared to Qwen3.5 Plus 2026-04-20?

GPT-5.1-Codex costs $1.25/M input tokens and Qwen3.5 Plus 2026-04-20 costs $0.4/M input tokens. Qwen3.5 Plus 2026-04-20 is $0.85/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 GPT-5.1-Codex and Qwen3.5 Plus 2026-04-20 on Rival?

This page shows a side-by-side comparison of GPT-5.1-Codex and Qwen3.5 Plus 2026-04-20 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

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Same lab, same size, long tail

  • GPT-5.1-Codex vs GPT-6 Luna ProSame lab
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  • Qwen3.5 Plus 2026-04-20 vs Qwen3.8 Omni FlashSame lab
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Model pages

  • GPT-5.1-Codex53 outputs, specs and price
  • Qwen3.5 Plus 2026-04-2056 outputs, specs and price
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