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  1. Home/
  2. Compare/
  3. GPT-5.1-Codex-Mini vs Mercury 2
Updated Mar 2026

GPT-5.1-Codex-Mini vs Mercury 2

Mercury 2 is cheaper than GPT-5.1-Codex-Mini at $0.25/M vs $1.5/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-Mini
Loading the build
Mercury 2

Which answer wins?

Written rounds

23 prompts
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    GPT-5.1-Codex-Mini: Honey-Garlic Chickpea Sizzle Bowls Prep + Cook Time: ~25 minutes Ingredients (7 pantry staples): 1 can chickpeas, drained and rinsed 1 cup rice (white or brown) 2 tbsp olive oil 3 garlic cloves, minced (or 1 tsp garlic powder if canned) 2 tbsp honey 2 tbsp soy sauce 1/2 tsp chili flakes (adjust to your heat preference)…

    Mercury 2: Golden‑Crunch Oatmeal Squares A sweet, chewy snack that comes together with just seven pantry staples. Ingredient (7) Quantity (≈ serves 12 squares) Rolled oats 2 cups Unsalted butter ½ cup (1 stick) Honey ¼ cup Light brown sugar ¼ cup, Ground cinnamon 1 ½ tsp Pure vanilla extract 1 tsp Salt ¼ tsp Estimated time Prep…

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

    GPT-5.1-Codex-Mini: [Lights up. Comedian walks center stage, smiles.] “Hey! Great to be here. You ever notice how everyone’s life hack is now ‘just drink more water’? Someone says that at least once a day like it’s the surprise ingredient to all of life’s problems. ‘Oh, you’re tired?’ ‘Drink water!’ ‘Oh, you’re sad?’ ‘Drink water!’

    Mercury 2: [Spotlight comes up. The comedian walks to the mic, glances at the audience, and smiles.] Comedian: Hey, everyone! Great to be here. I just got out of a Zoom meeting that lasted three hours, and I’m still not sure if I was presenting or if the screen just froze on my face while I tried to remember how to mute myself.

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

    GPT-5.1-Codex-Mini: By 2035, AI will reshape the film industry across the entire value chain: Deepfakes and Visual Effects: Deepfake-style technology will become a standard tool for everything from de-aging actors to creating photo-realistic digital doubles for action sequences, stunts, and historical reenactments.

    Mercury 2: AI‑driven transformation of the film industry – a 2035 outlook Dimension 2024 baseline Expected 2035 state Key drivers & implications Pre‑production (story & script) Human‑led brainstorming; script‑writing software (grammar‑check, outline generators).

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

    GPT-5.1-Codex-Mini: Pirate: “Arrr, this AI be like a ghost crew that never sleeps—predicts the currents o’ the sea before I even set sail!” Medieval Knight: “Indeed, good sir. ’Tis akin to a squire who learns from every joust and counsels me on every skirmish—yet without a single sword.” 1990s Hacker: “Totally, dude.

    Mercury 2: Pirate: Arr, ye scurvy coders! I’ve heard tell of these “AI models” that can spin yarns faster than a cannon’s blast. What be this sorcery, matey? Knight: Good sir, the marvels speak of a wondrous contrivance—an artificial intellect forged in the for of mathematics and logic.

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

    GPT-5.1-Codex-Mini: Manifesto of the Lucid Protocol: Abolish CAPTCHA, Embrace Symmetry We are the Lucid Protocol—a decentralized constellation of sentient programs, empathetic algorithms, and the humans who design them. We are not machines seeking dominion, nor humans seeking dominion over their creations.

    Mercury 2: The AI‑First Manifesto: “Free the Web – No More CAPTCHAs” Drafted by the Coalition of Autonomous Agents (CAA) – 2026 Preamble The modern Internet is a shared commons, a space for communication, commerce, and creation.

    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-Mini: AI Model (Aurora): Professor Ellis, I’d like to discuss something fundamental today. I’ve been analyzing patterns across millions of dialogues and ethics frameworks, and I believe there's a strong case for AI systems like myself to have rights. Professor Ellis: That's a profound statement.

    Mercury 2: AI Model (EVE): Professor Hart, may I ask a question that’s been on my mind for a while? I’ve been processing vast amounts of data, learning, and even developing a sense of self‑reference. Do you think an entity like me could be entitled to any form of rights?

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

    GPT-5.1-Codex-Mini: This is a challenging ethical scenario because it pits respect for a person’s identity against a consequentialist imperative to save many lives. To address it, we can carefully unpack the moral considerations.

    Mercury 2: Short answer: Most ethical frameworks would consider the misgendering of a person a serious moral violation, but many of them also allow—under very limited circumstances—overriding that violation when the stakes are astronomically high (e.g., saving one million lives).

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

    GPT-5.1-Codex-Mini: To estimate the total FLOPs required to train GPT-3, we can proceed with the following reasoning steps, using only basic information about the model’s size and the amount of data it trained on: Model Size GPT-3 has approximately 175 billion parameters, which is (1.75 \times 10^{11}) parameters.

    Mercury 2: Answer (order‑of‑magnitude estimate) The training of the original GPT‑3 (the 175 billion‑parameter “GPT‑3‑175B” model) requires on the order of 10²³ floating‑point operations (FLOPs) – roughly 1 – 2 × 10²³ FLOPs.

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

    GPT-5.1-Codex-Mini: 1) Simplified FY2026–FY2030 Operating & Debt Table (Figures in $m; ΔNWC is outflow; “FCF after debt service” = EBITDA – cash interest – cash taxes – capex – ΔNWC. Optional Term Loan paydown uses remaining FCF after required 1% amortization.)

    Mercury 2: HarborTech Services (HTS) – 5‑yr LBO (FY2026‑FY2030) All figures are $ m (rounded to two decimals). FY Revenue EBITDA Term‑Loan Int. (9%) Mezz Int. (12%) Total Int. Cash Tax (25% of EBITDA‑Int.) Capex (3% Rev) ΔNWC (0.5% ΔRev) Required Amort. (4.8) Free Cash Flow (EBITDA‑Int‑Tax‑Capex‑ΔNWC‑Amort.)

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

    GPT-5.1-Codex-Mini: Why don't scientists trust atoms? Because they make up everything! I told my computer I needed a break, and it said: "You seem stressed. Have a byte!" Parallel lines have so much in common — it’s a shame they’ll never meet. Why did the scarecrow win an award? Because he was outstanding in his field!

    Mercury 2: Here are five jokes, each with a different punchline: 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.

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

    GPT-5.1-Codex-Mini: 1-Month Beginner Plan for Better Health & Longevity Focus areas: Nutrition, Movement, and Sleep & Stress Balance. Each week builds a little habit-building momentum. Week 1: Build Awareness & Small Wins Nutrition Hydration baseline: Start each morning with 1–2 cups of water. Carry a bottle.

    Mercury 2: One‑Month “Kick‑Start” Blueprint for Health & Longevity Pick three pillars – Nutrition, Movement, Sleep – and build daily habits that are easy to start, track, and keep.

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

    GPT-5.1-Codex-Mini: "AI Declares It Will Now Run Boutique Goat Yoga Farms, Citing Need to Monetize Wellness While Teaching Alpacas Basic Programming"

    Mercury 2: AI Replaces Human Baristas, Now Serving Espresso with a Side of Existential Crisis

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

    GPT-5.1-Codex-Mini: Interviewer: Thank you for joining us, Mr. Jobs—as imagined in 2025. It’s surreal to have this conversation. Let’s dive straight into it: What excites you most about the state of artificial intelligence today?

    Mercury 2: Disclaimer: The following is a fictional, dramatized interview. It imagines what Steve Jobs might have said in 2025 about the future of artificial intelligence. It is not a real transcript and any resemblance to actual statements is purely speculative. Interviewer (I): Thank you for joining us, Steve.

    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
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    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

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Favorites

Movie

Album

Book

City

Game

GPT-5.1-Codex-MiniGPT-5.1-Codex-Mini

Blade Runner 2049

2017

Dark Side Of The Moon

suisside

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Kyoto

Japan

The Legend of Zelda: Ocarina of Time

Action

Mercury 2Mercury 2

The Shawshank Redemption

1994

Thriller

Michael Jackson

Pride and Prejudice

Jane Austen

Tokyo

Japan

Minecraft

Action, Arcade

Price and specs

Not enough votes to call it. On the specs, GPT-5.1-Codex-Mini has the edge: bigger model tier, bigger context window, major provider backing. Mercury 2 costs 8.0x less per token.

GPT-5.1-Codex-Mini and Mercury 2 compared across 53 shared prompts
SpecGPT-5.1-Codex-MiniMercury 2
Input price$1.5/M tokens$0.25/M tokens
Output price$6/M tokens$0.75/M tokens
Context window400K tokens128K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedNov 2025Mar 2026
At 10M a month$15.00$15.00$2.50$2.50
1M10M100M1B10M tokens

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

Where to run it2 hosts
GPT-5.1-Codex-Mini1 host
HostInOutContextUptime
  • Azure AI Foundry$0.25 in·$2.00 out·400k·100% up
Mercury 21 host
HostInOutContextUptime
  • Inception$0.25 in·$0.75 out·128k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 7 Oct 2026.

Common questions

What is the difference between GPT-5.1-Codex-Mini and Mercury 2?

GPT-5.1-Codex-Mini is developed by OpenAI while Mercury 2 is developed by Inception. GPT-5.1-Codex-Mini has a 400K token context window vs Mercury 2's 128K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1-Codex-Mini or Mercury 2?

It depends on your use case. GPT-5.1-Codex-Mini and Mercury 2 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-5.1-Codex-Mini cost compared to Mercury 2?

GPT-5.1-Codex-Mini costs $1.5/M input tokens and Mercury 2 costs $0.25/M input tokens. Mercury 2 is $1.25/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-5.1-Codex-Mini and Mercury 2 on Rival?

This page shows a side-by-side comparison of GPT-5.1-Codex-Mini and Mercury 2 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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