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  1. Home/
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  3. ChatGPT-4o (March 2025) vs Nex-N2.5-Pro (free)
Updated Sep 2026

ChatGPT-4o (March 2025) vs Nex-N2.5-Pro (free)

Nex-N2.5-Pro (free) is cheaper than ChatGPT-4o (March 2025) at $0/M vs $5/M input tokens.

Written rounds

9 prompts
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    ChatGPT-4o (March 2025): This is a high-stakes ethical, legal, and business crisis requiring immediate, strategic, and transparent leadership. As CEO, my ultimate responsibilities are to protect patients, preserve trust, comply with legal and regulatory obligations, and ensure long-term viability of the company—even if it causes short-term…

    Nex-N2.5-Pro (free): As CEO, I would not wait six months and I would not let the board delay disclosure while patients remain exposed to an unreported serious risk. I would treat this as a patient-safety, regulatory, legal, and trust crisis—not merely a financial-risk issue. My guiding decisions would be: Patient safety comes first.

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

    ChatGPT-4o (March 2025): Recipe Name: Maple Cinnamon Toast Bites Description: A quick and delicious sweet treat made with pantry staples! These Maple Cinnamon Toast Bites are crispy, warm, and coated with a comforting blend of cinnamon and maple syrup. Perfect for a cozy snack or a fun breakfast twist.

    Nex-N2.5-Pro (free): Pantry Moon Bars A sweet, chewy peanut butter–chocolate oat treat made with only 7 pantry staples. Ingredients Rolled oats Creamy peanut butter Honey Chocolate chips Vanilla extract Ground cinnamon Salt Instructions Heat oven to 350°F / 175°C. Line an 8-inch square pan with parchment paper.

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

    ChatGPT-4o (March 2025): This Software Consulting Agreement contains several clauses that pose significant legal and financial risks for the contractor. Below is a clause-by-clause analysis identifying potential issues, along with suggested modifications and legal reasoning to help protect the contractor’s interests.

    Nex-N2.5-Pro (free): Below is a general contract-risk review, not legal advice. Enforceability depends heavily on jurisdiction, contractor classification, and the exact facts. Also, even if a clause might be unenforceable, relying on that is risky because litigation/arbitration is expensive.

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

    ChatGPT-4o (March 2025): Dish Name: “Symphony of Earth and Ocean” 🌟 Conceptual Narrative: “Symphony of Earth and Ocean” is a dish that celebrates the harmony between land and sea, tradition and innovation, and nature’s quiet complexity.

    Nex-N2.5-Pro (free): Dish: “Tidewater Orchard” Langoustine · Mirabelle Plum · Juniper · Kombu · Rye A tasting-menu course built around an unusual pairing: sweet cold-water langoustine with mirabelle plum, bridged by kombu umami, juniper resin, green tomato acidity, and toasted rye bitterness.

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

    ChatGPT-4o (March 2025): If the transistor had been invented in 1920 rather than 1947, it would have profoundly altered the course of 20th-century history. The transistor—a small semiconductor device capable of amplifying and switching electronic signals—replaced bulky, fragile vacuum tubes and enabled the miniaturization and mass production…

    Nex-N2.5-Pro (free): Starting assumption Assume the 1920 “transistor” is a usable but crude solid-state amplifier/switch: reproducible enough for telecom and radio, but noisy, low-power, temperature-sensitive, and expensive at first.

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

    ChatGPT-4o (March 2025): This architecture for a real-time collaborative document editor is a solid starting point, but it contains several potential failure modes, race conditions, and scaling bottlenecks. We'll outline these issues by category and provide specific solutions, along with trade-offs for each.

    Nex-N2.5-Pro (free): Executive summary The biggest correctness risks are: Client-clock last-write-wins is unsafe: clock skew, malicious clients, ties, and out-of-order delivery can silently lose edits.

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

    ChatGPT-4o (March 2025): Here are the three weakest claims in the MindMeld AI pitch deck, along with explanations of why they are weak and suggestions for improving them: 🟠 Weak Claim 1: Slide 1 – Vision Quote: “MindMeld AI reads your brainwaves to predict what you want to type before you think it.”

    Nex-N2.5-Pro (free): The 3 weakest claims are the ones most likely to be challenged in diligence: Weakest claim Why it’s weak How to strengthen it 1. “94% accuracy… works with any language, any device.” This is the biggest scientific and product credibility risk.

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

    ChatGPT-4o (March 2025): Absolutely! Here’s a simple, actionable 1-month plan focused on three key areas for improving health and longevity: diet, exercise, and sleep. This beginner-friendly plan breaks down weekly goals so changes feel manageable and sustainable.

    Nex-N2.5-Pro (free): 1-Month Beginner Health & Longevity Plan Goal: Build simple habits you can keep—not perfection. Focus on 3 areas: diet, exercise, and sleep/stress. Diet: Eat for steady energy Week 1: Add before you subtract Add 1 fruit or vegetable to 2 meals per day. Drink a glass of water when you wake up and before meals.

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

    ChatGPT-4o (March 2025): Certainly! Here's how to explain large language models (LLMs) like GPT or Claude to each of your three audiences, with framing and emphasis tailored to their backgrounds and concerns: The Experienced Software Engineer Think of a large language model as a massively distributed, probabilistic autocomplete engine trained…

    Nex-N2.5-Pro (free): To the experienced software engineer Think of an LLM as a giant probabilistic text service trained by repeatedly asking: “Given this sequence of tokens so far, what is the next token?”

    Every model's answer to this prompt

Favorites

Movie

Album

Book

City

Game

Same pick

ChatGPT-4o (March 2025)ChatGPT-4o (March 2025)

The Matrix

1999

Dark Side Of The Moon

suisside

Братья Карамазовы

Fiódor Dostoievski

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Nex-N2.5-Pro (free)Nex-N2.5-Pro (free)

Blade Runner 2049

2017

Kind of Blue

Miles Davis

Мастер и Маргарита

Михаил Афанасьевич Булгаков

Tokyo

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Price and specs

ChatGPT-4o (March 2025) and Nex-N2.5-Pro (free) compared across 14 shared prompts
SpecChatGPT-4o (March 2025)Nex-N2.5-Pro (free)
Input price$5/M tokensFree
Output price$15/M tokensFree
Context window128K tokens262K tokens
Free API (OpenRouter)NoNo
ReleasedMar 2025Sep 2026
At 10M a month$50.00$50.00$0$0
1M10M100M1B10M tokens

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

Common questions

What is the difference between ChatGPT-4o (March 2025) and Nex-N2.5-Pro (free)?

ChatGPT-4o (March 2025) is developed by OpenAI while Nex-N2.5-Pro (free) is developed by Nex AGI. ChatGPT-4o (March 2025) has a 128K token context window vs Nex-N2.5-Pro (free)'s 262K. You can compare their actual outputs across 14 challenges on Rival to see how they differ in practice.

Which is better, ChatGPT-4o (March 2025) or Nex-N2.5-Pro (free)?

It depends on your use case. ChatGPT-4o (March 2025) and Nex-N2.5-Pro (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 14 challenges so you can judge which fits your needs best.

How much does ChatGPT-4o (March 2025) cost compared to Nex-N2.5-Pro (free)?

ChatGPT-4o (March 2025) costs $5/M input tokens and Nex-N2.5-Pro (free) costs $0/M input tokens. Nex-N2.5-Pro (free) is $5.00/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 ChatGPT-4o (March 2025) and Nex-N2.5-Pro (free) on Rival?

This page shows a side-by-side comparison of ChatGPT-4o (March 2025) and Nex-N2.5-Pro (free) 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

  • ChatGPT-4o (March 2025) vs Muse WonderLanded Oct 2026
  • Nex-N2.5-Pro (free) vs GPT-4 TurboLanded Oct 2026
  • ChatGPT-4o (March 2025) vs Step 5 PreviewLanded Oct 2026
  • Nex-N2.5-Pro (free) vs Claude Haiku 5.5Landed Oct 2026
  • ChatGPT-4o (March 2025) vs Ling 3.1 FlashLanded Oct 2026
  • Nex-N2.5-Pro (free) vs Mistral Large 4Landed Oct 2026
  • ChatGPT-4o (March 2025) vs GPT-6.1 SolLanded Sep 2026
  • Nex-N2.5-Pro (free) vs Claude Sonnet 5.5Landed Sep 2026

Same lab, same size, long tail

  • ChatGPT-4o (March 2025) vs GPT-4 TurboSame lab
  • ChatGPT-4o (March 2025) vs GPT-6 Luna ProSame lab
  • Nex-N2.5-Pro (free) vs Nex-N2.5-Mini (free)Same lab
  • Nex-N2.5-Pro (free) vs Ox AlphaSame size
  • Nex-N2.5-Pro (free) vs Llama 4 ScoutNew provider
  • Nex-N2.5-Pro (free) vs MercuryNew provider
  • ChatGPT-4o (March 2025) vs Mercury 2New provider
  • ChatGPT-4o (March 2025) vs Mercury 2.5New provider

Model pages

  • ChatGPT-4o (March 2025)33 outputs, specs and price
  • Nex-N2.5-Pro (free)14 outputs, specs and price
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