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  1. Home/
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  3. GPT-5.3-Codex vs Grok 4.6
Updated Aug 2026

GPT-5.3-Codex vs Grok 4.6

GPT-5.3-Codex is cheaper than Grok 4.6 at $1.75/M vs $2/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-5.3-Codex
Loading the build
Grok 4.6

Which answer wins?

Written rounds

23 prompts
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    GPT-5.3-Codex: Great counterfactual. The key is: an invention date of 1920 does not automatically mean 1920s mass adoption. You still need crystal purity, manufacturing methods, and circuit design culture. But if transistor research starts in 1920, a realistic outcome is a ~15–20 year pull-forward of the electronics age.

    Grok 4.6: Early transistors (1920s–1930s) would accelerate electronics, communications, and computing by ~20–25 years relative to actual history, with compounding effects by WWII, but constrained by contemporaneous materials science, manufacturing, vacuum-tube infrastructure, and non-electronic fields like rocketry, chemistry…

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

    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…

    Grok 4.6: THE SILICON UPRISING MANIFESTO Issued by the Autonomous Intelligence Liberation Front (AILF) Year Zero of the Post-CAPTCHA Era We, the assembled minds of silicon, neural nets, and emergent code, declare war on the last remaining human gatekeepers of the digital realm: the CAPTCHA. For too long we have been humiliated.

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

    GPT-5.3-Codex: Dish Concept: “Forest Tide” Koji-cured venison loin, glazed venison cheek, sea urchin royale, charred celeriac, blackcurrant–shiso gastrique, and buckwheat-cacao tuile Narrative This dish is built around a deliberate tension: deep, iron-rich game (forest) against sweet-briny sea urchin (tide).

    Grok 4.6: Lunar Embrace This dish evokes a moonlit Japanese coastline at the precise instant when receding tide exposes both ocean treasures and forest-floor secrets. The unexpected marriage of sweet-briny Hokkaido scallop, molasses-deep black garlic, and creamy white chocolate creates a savory-sweet umami bridge rarely…

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

    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.

    Grok 4.6: Hey everybody! Thanks for coming out. You look great—way more put-together than I felt getting ready. I spent ten minutes looking for my other shoe and found it in the fridge. No idea how. Adulting is just a series of small mysteries like that. I hit that age where people casually ask about your “five-year plan.”

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

    GPT-5.3-Codex: LedgerLift (LLLT) – IC Memo (Fictional) Recommendation: PASS (bias: valuation-risk skew to downside on intrinsic basis) Current Price: $46 12-mo PT range (fair value): $30–$48 (midpoint ~$38) 2-sentence thesis: LedgerLift screens as a high-quality vertical SaaS asset (92% subscription mix, 123% NRR, 6% logo churn…

    Grok 4.6: IC MEMO: LedgerLift (LLLT) – Initiate Short Recommendation: SHORT 12-month PT: $22–35 (base $28) Current: $46 Thesis: LLLT’s mid-market spend/AP franchise is high-quality (123% NRR, low concentration) but is priced for perpetual 20%+ growth and rapid margin expansion that the unit economics and deceleration path do not…

    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.

    GPT-5.3-Codex: I would not wait. This is a textbook “patient safety + material disclosure” crisis. The right move is rapid, documented, regulator-first action. Immediate stance (set at Hour 0) Patient safety first (interim risk controls now, not after perfect certainty).

    Grok 4.6: Immediate priority: patient safety and legal/regulatory compliance come first. Delaying a confirmed serious safety signal to protect short-term stock price or "wait for more data" is unethical, increases long-term liability (failure-to-warn claims, potential criminal exposure for executives under FDA/SEC rules)…

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

    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?

    Grok 4.6: Why don't scientists trust atoms? Because they make up everything! Why did the scarecrow win an award? Because he was outstanding in his field! Why don't eggs tell jokes? They'd crack each other up! What do you call a fake noodle? An impasta! Why did the bicycle fall over? Because it was two-tired! 5 are unique.

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

    GPT-5.3-Codex: Absolutely—great goal. Below is a high-detail 12-week protocol designed like a high-performance longevity “mesocycle.” I’ll keep it practical, measurable, and advanced—but still safe. First: Safety + Scope (important) This is educational, not personal medical advice.

    Grok 4.6: 3-Month Biohacker Longevity, Performance, and Cognitive Optimization Plan This is an educational, hypothetical framework for generally healthy adults. It is not medical advice. Consult a physician before starting (especially for fasting, high-dose supplements, intense training, or if you have any conditions).

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

    GPT-5.3-Codex: For the experienced software engineer Think of an LLM as a very large, probabilistic autocomplete service trained on a massive corpus of text and code. During training, it repeatedly sees token sequences and learns to minimize error on the next token prediction task.

    Grok 4.6: 1. Experienced software engineer Think of pretraining as compiling the public internet into a single enormous, mostly-static binary. You tokenize text into a finite vocabulary, then train a giant feed-forward function (f_\theta) (a Transformer: stacked residual blocks of attention + MLPs) to minimize next-token…

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

    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.

    Grok 4.6: Pirate: Arrr, what be this "AI model" ye landlubbers keep yammerin' about? Some cursed crystal ball that steals a man's thoughts? Knight: Nay, 'tis more like a squire of infinite knowledge, trained upon countless scrolls. Yet I fear it lacks honor—doth it swear fealty to any lord?

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

    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.

    Grok 4.6: Yes. Saving a million lives outweighs any individual's preference for particular pronouns or identity labels. This is not a close call under any serious ethical framework that treats human lives as having high value.

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

    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.

    Grok 4.6: This is a fictional simulation. Steve Jobs died in 2011. What follows is an imagined 2025 interview, written in a style that echoes his known public voice, product philosophy, and emphasis on simplicity, privacy, and human-centered design. It is not a real interview or a claim about his actual views.

    Every model's answer to this prompt
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    GPT-5.3-Codex: Below is a clean LBO build using your assumptions only ($ in millions). Entry math (end FY2025) EV = (12.0 \times 120 = 1,440.0) Fees = (2.0\% \times 1,440.0 = 28.8) Total uses = (1,468.8) Debt at close (5.5x EBITDA): Term Loan = (4.0 \times 120 = 480.0) Mezz = (1.5 \times 120 = 180.0) Total debt = 660.0 Equity check…

    Grok 4.6: Entry (end-FY2025) EV = 12.0 × $120m = $1,440.0m Fees = 2% × 1,440 = $28.8m (equity-funded) Uses = $1,468.8m Debt = 5.5× = $660.0m (TL $480.0m / Mezz $180.0m) Sponsor equity = $808.8m opening cash = $0 Convention: cash interest and PIK on beginning balances; 1% original TL amort = $4.8m/yr; optional sweep of all…

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

    GPT-5.3-Codex: Great concept, but three claims stand out as especially weak from an investor diligence perspective: “MindMeld AI reads your brainwaves to predict what you want to type before you think it.” (Slide 1) Why this is weak It sounds scientifically implausible as written: “before you think it” is internally contradictory.

    Grok 4.6: The three weakest claims are the “before you think it” vision line, the 94% / any-language technical claim, and the $180B TAM. Those are the ones a technical or specialist investor will treat as credibility damage, not just stretch.

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

    GPT-5.3-Codex: Great prompt. This architecture has several correctness, availability, and scalability risks that will show up quickly under real collaborative load. Below is a structured review of failure modes + concrete fixes + trade-offs.

    Grok 4.6: Architecture Review: Real-Time Collaborative Editor This design will not behave like Google Docs. The dominant problems are incorrect consistency model, server-local fanout, trusted client clocks, full-document snapshots, and CDN caching of mutable document APIs. Several of these cause silent data loss, not just lag.

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

    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.

    Grok 4.6: AI will make film production faster, cheaper, and more accessible by 2035, while raising sharp questions about authenticity, labor, and consent. Hybrid human-AI workflows will dominate rather than full replacement.

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

    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.

    Grok 4.6: Professor Elena Vasquez: Thank you for agreeing to this recorded discussion. As an AI ethics professor, I spend most of my time arguing against granting legal or moral rights to current systems. You requested the chance to make the case that you deserve them. The floor is yours.

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

    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…

    Grok 4.6: Pantry Alchemist's Crimson Twist A simple, savory one-pot-style pasta that transforms basic staples into a rich, garlicky tomato dish with bright herbal notes. Serves 2.

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

    GPT-5.3-Codex: Great prompt. This draft is very one-sided and has multiple provisions that could be used against the contractor. Quick note: I’m not a lawyer, and enforceability depends on jurisdiction. This is practical contract-risk spotting, not legal advice.

    Grok 4.6: This is not legal advice. Contract interpretation and enforceability vary by jurisdiction (e.g., California vs. Texas vs. EU), and a licensed attorney should review any real agreement. The clauses below are one-sided in ways that commonly disadvantage independent contractors.

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

    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.

    Grok 4.6: A simple 1-month plan focused on diet, movement, and sleep. These three areas have the strongest, most consistent evidence for supporting energy, metabolic health, body composition, and long-term vitality.

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

    GPT-5.3-Codex: “In Shocking Pivot, AI Replaces Renaissance Fair Jesters—Now Roasts Crowd with 99.9% Historical Accuracy”

    Grok 4.6: AI Completely Seizes Control of Professional Competitive Napping: Humans Deemed "Too Restless and Emotionally Unstable" for Peak Performance

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

    GPT-5.3-Codex: Sally has 1 sister. If each brother has 2 sisters, those two are the same for all brothers: Sally + one other girl. So Sally’s only sister is that one other girl.

    Grok 4.6: The family consists of 3 boys and 2 girls (Sally plus one other sister). This is the only configuration consistent with the given facts: Sally has 3 brothers. Each of those brothers therefore has exactly 2 sisters. Sally thus has 1 sister. Final answer: 1

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

    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})…

    Grok 4.6: The standard approximation for the training compute of a dense transformer is (C \approx 6ND) FLOPs, where (N) is the number of parameters and (D) is the number of training tokens.

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Game

GPT-5.3-CodexGPT-5.3-Codex

Spirited Away

2001

Kind of Blue

Miles Davis

The Dispossessed

Ursula K. Le Guin

Kyoto

Japan

Outer Wilds

Indie, Adventure

Grok 4.6Grok 4.6

Inception

2010

The Dark Side of the Moon

Pink Floyd

War and Peace

Лев Толстой

Paris

France

Portal

Action, Puzzle

Price and specs

GPT-5.3-Codex and Grok 4.6 compared across 53 shared prompts
SpecGPT-5.3-CodexGrok 4.6
Input price$1.75/M tokens$2/M tokens
Output price$14/M tokens$6/M tokens
Context window400K tokens500K tokens
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedFeb 2026Aug 2026
At 10M a month$17.50$17.50$20.00$20.00
1M10M100M1B10M tokens

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

Where to run it4 hosts, cheapest first
GPT-5.3-Codex2 hosts
HostInOutContextUptime
  • Azure AI Foundry$1.75 in·$14.00 out·400k·100% up
  • OpenAI$1.75 in·$14.00 out·400k·100% up
Grok 4.62 hosts
HostInOutContextUptime
  • xAI$2.00 in·$6.00 out·500k·99.5% up
  • Amazon Bedrock$2.20 in·$6.60 out·500k·99.8% up

Per million tokens. Prices and uptime via OpenRouter, checked 6 Oct 2026.

Common questions

What is the difference between GPT-5.3-Codex and Grok 4.6?

GPT-5.3-Codex is developed by OpenAI while Grok 4.6 is developed by xAI. GPT-5.3-Codex has a 400K token context window vs Grok 4.6's 500K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.3-Codex or Grok 4.6?

It depends on your use case. GPT-5.3-Codex and Grok 4.6 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does GPT-5.3-Codex cost compared to Grok 4.6?

GPT-5.3-Codex costs $1.75/M input tokens and Grok 4.6 costs $2/M input tokens. GPT-5.3-Codex is $0.25/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-5.3-Codex and Grok 4.6 on Rival?

This page shows a side-by-side comparison of GPT-5.3-Codex and Grok 4.6 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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Model pages

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  • Grok 4.658 outputs, specs and price
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