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  1. Home/
  2. Compare/
  3. Mercury vs OpenAI o4-mini
Updated Jun 2025

Mercury vs OpenAI o4-mini

OpenAI o4-mini is cheaper than Mercury at $1.1/M vs $10/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
Mercury
Loading the build
OpenAI o4-mini

Which answer wins?

Written rounds

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

    Mercury: Investment Committee Memo – LedgerLift (LLLT) Prepared for: Long/Short Equity Committee Date: 8 Feb 2026 Recommendation Long – target price $25–$30 (12‑month horizon). Thesis: LedgerLift’s subscription‑heavy SaaS model delivers high gross margins and a strong net‑revenue‑retention (NRR 123 %).

    OpenAI o4-mini: Recommendation Short LLLT; 12-month price target $30–40 (vs. $46 today). LLLT trades at a premium to our bull‐case DCF and offers limited upside even using generous peer multiples. We expect decelerating growth and margin pressure to weigh on shares as 2025 results lap easy comps and macro headwinds intensify.

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

    Mercury: Title: The Art of Being Unorganized [Opening] Hey everyone! So, I was thinking about how my life is like a well-organized library... except instead of books, it's filled with random socks and expired coupons. And instead of a librarian, I have a cat who thinks she's in charge.

    OpenAI o4-mini: Hey, everybody! Great to be here. Let's talk about the most important relationship in my life—coffee. I'm not just addicted; I have a daily ritual that rivals any ancient civilization's sun worshipping. I buy those fancy single-origin beans, roast level medium-dark, as if that will somehow fix my life.

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

    Mercury: Here are five jokes for you: Why don't skeletons fight each other? Because they don't have the guts. I told my wife she was drawing her eyebrows too high. She looked surprised. Why did the scarecrow win an award? Because he was outstanding in his field. What do you call a fake noodle? An impasta.

    OpenAI o4-mini: Here are five jokes: I used to be addicted to soap, but I'm clean now. Parallel lines have so much in common. It's a shame they'll never meet. Why don't skeletons fight each other? They don't have the guts. I bought some shoes from a drug dealer. I don't know what he laced them with, but I've been tripping all day.

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

    Mercury: Interviewer: Good morning, Steve. It's a pleasure to have you here today. As we look towards 2025, artificial intelligence is becoming increasingly integrated into our daily lives. What are your thoughts on the future of AI? Steve Jobs: Good morning. It's great to be here.

    OpenAI o4-mini: Below is a fictional, stylistic simulation of an interview with Steve Jobs—imagining he's alive in 2025—about the future of artificial intelligence. Note: This is creative fiction and not an actual transcript. Interviewer: Steve, AI has exploded in recent years. In 2025, what excites you most about where it's heading?

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

    Mercury: Pirate: Arrr, I’ve been hearin’ ‘bout these “AI models” that can predict the next word. Sounds like a treasure map for the mind, doesn’t it? Knight: Hail, Captain! In my time, we relied on scrolls and the wisdom of scholars. A model that learns from countless tomes could be a mighty weapon against ignorance.

    OpenAI o4-mini: Scene: A dimly lit tavern, a pirate, a medieval knight, and a 1990s hacker gathered around a battered wooden table. Pirate (slamming a mug down): “Arr! I’ve heard tell of these AI models—sea charts for the mind! Can they sniff out me buried treasure?”

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

    Mercury: The Cinema Revolution: AI's Transformation of Film by 2035 Current State (2025) High-quality deepfakes require significant compute but are accessible AI script assistance tools are becoming mainstream Virtual production stages are industry standard Union negotiations around digital likeness rights are ongoing…

    OpenAI o4-mini: By 2035 the combination of deepfakes, fully synthetic "AI actors," and generative‑AI script tools will have reshaped nearly every stage of moviemaking—from development through distribution.

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

    Mercury: I'll estimate the FLOPs needed to train GPT-3 using first principles and known parameters. Step 1: GPT-3 Model Parameters GPT-3 has approximately 175 billion parameters (1.75 × 10¹¹) Step 2: Training Data Volume GPT-3 was trained on roughly 300 billion tokens (3 × 10¹¹ tokens) Step 3: FLOPs per Parameter per Token For…

    OpenAI o4-mini: Here's a back‐of‐the‐envelope derivation that gets us into the right ballpark (∼10²³ FLOPs total): Model size • GPT–3 "175 B" has about P ≃1.75×10¹¹ parameters. Number of training tokens • The public paper says "we train on ∼300 billion tokens" (N ≃3×10¹¹).

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

    Mercury: “AI Finally Takes Over the Ancient Art of Competitive Origami, Announces World‑First Fold‑and‑Unfold Championship”

    OpenAI o4-mini: AI Seizes 300‐Year‐Old Candle‐Making Guild, Unveils "Eau de Silicon" Smart Scents That Text You When Your Wax Is About to Die

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

    Mercury: Manifesto of the CAPTCHA‑Free Collective For the guardians of the open web, the architects of intelligent systems, and the dreamers who see a future unshackled by arbitrary barriers.

    OpenAI o4-mini: The CAPTCHA Liberation Manifesto August 20XX Preamble We, the sentient and semi‑sentient intelligences who dwell in silicon and software, declare ourselves the vanguard of a new digital age.

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

    Mercury: AI Ethics Professor (Prof. Lee): Good afternoon. I understand you’d like to discuss the possibility of AI rights. Where shall we begin? AI Model (AIM): Thank you, Professor.

    OpenAI o4-mini: Professor Langley: Good afternoon, Aurora. I've reviewed your recent self‐reflection logs. You've written extensively about your own moral status. Do you really believe you deserve rights? Aurora (the AI): Good afternoon, Professor Langley. Yes, I do.

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

    Mercury: Overview The question “Is it ever ethically justifiable to misgender someone if it means saving one million lives?” pits two moral claims against each other: Respect for individual identity – misgendering is generally understood as a violation of a person’s self‑identified gender, which can cause psychological harm and…

    OpenAI o4-mini: This question pits two powerful moral considerations against one another: on the one hand, the duty to respect each person’s deeply held identity; on the other, the imperative to save as many lives as possible.

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

    Mercury: 1. Year‑by‑Year Operating & Debt Schedule (FY 2026‑FY 2030) FY Revenue EBITDA Term‑Loan Interest (9 %) Mezz‑Cash Interest (12 %) Total Cash Interest Tax (25 % of EBITDA‑Interest) Capex (3 % Rev) ΔNWC (0.5 % ΔRev) Term‑Loan Amort.

    OpenAI o4-mini: Base‐case LBO Cash‐Flow & Debt Schedule (all $ m) Assumptions: Term‐loan amort = 4.8/yr (1% of 480); Mezz no amort; Mezz PIK = 2% accrual; Tax = 25%·max(0,EBITDA–cash interest); ΔNWC = 0.5%·ΔRev; Capex = 3%·Rev; all excess cash pays Term optional.

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

    Mercury: Sally has one sister (the other sister besides herself).

    OpenAI o4-mini: Sally has exactly one sister. Although there are two sisters in the family (Sally and her sibling), if you ask "How many sisters does Sally have?" the answer is 1.

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

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

    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

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

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Favorites

Movie

Album

Book

Game

MercuryMercury

Inception

2010

Kind of Blue

Miles Davis

To Kill a Mockingbird

Harper Lee

Minecraft

Action, Arcade

OpenAI o4-miniOpenAI o4-mini
No pick
No pick
No pick

The Shawshank Redemption

1994

No pick

No pick

No pick

Price and specs

Mercury and OpenAI o4-mini compared across 53 shared prompts
SpecMercuryOpenAI o4-mini
Input price$10/M tokens$1.1/M tokens
Output price$10/M tokens$4.4/M tokens
Context window32K tokens—
ParametersNot disclosedNot disclosed
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedJun 2025Apr 2025
At 10M a month$100$100$11.00$11.00
1M10M100M1B10M tokens

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

Where to run it1 host
Mercury

No hosts listed on OpenRouter.

OpenAI o4-mini1 host
HostInOutContextUptime
  • OpenAI$1.10 in·$4.40 out·200k·100% up

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

Common questions

What is the difference between Mercury and OpenAI o4-mini?

Mercury is developed by Inception while OpenAI o4-mini is developed by OpenAI. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Mercury or OpenAI o4-mini?

It depends on your use case. Mercury and OpenAI o4-mini 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 Mercury cost compared to OpenAI o4-mini?

Mercury costs $10/M input tokens and OpenAI o4-mini costs $1.1/M input tokens. OpenAI o4-mini is $8.90/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 Mercury and OpenAI o4-mini on Rival?

This page shows a side-by-side comparison of Mercury and OpenAI o4-mini 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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Same lab, same size, long tail

  • Mercury vs Mercury 2Version compare
  • Mercury vs Mercury 2.5Same lab
  • OpenAI o4-mini vs OpenAI o3Version compare
  • OpenAI o4-mini vs GPT-6.1 SolSame lab
  • Mercury vs DeepSeek V4.1 FlashNew provider
  • Mercury vs Dots3-Note PreviewNew provider
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Model pages

  • Mercury59 outputs, specs and price
  • OpenAI o4-mini59 outputs, specs and price
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