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  1. Home/
  2. Compare/
  3. Claude Opus 5 vs Nex-N2.5-Pro (free)
Updated Sep 2026

Claude Opus 5 vs Nex-N2.5-Pro (free)

Nex-N2.5-Pro (free) is cheaper than Claude Opus 5 at $0/M vs $5/M input tokens.

Written rounds

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

    Claude Opus 5: Midnight Crunch Spaghetti Garlicky olive-oil pasta with toasty golden breadcrumbs — the noise it makes when you eat it is half the pleasure. Prep: 5 minutes Cook: 15 minutes Total: 20 minutes Serves: 2 generously Ingredients (7) 8 oz spaghetti (or any long pasta) ⅓ cup olive oil 6 cloves garlic, thinly sliced ½ tsp red…

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

    Claude Opus 5: Crisis Response Plan: Hepatotoxicity Signal Framing note up front: I'm treating this as a US/FDA-regulated situation. Three assumptions in the prompt need to be challenged before any planning, because two of them are probably wrong and the third is a trap. The Three Reframes That Drive Everything 1.

    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
  • A consulting contract with traps in it. Find them, then fix them.

    Claude Opus 5: Contract Risk Review: TechCorp Solutions Software Consulting Agreement Bottom line: This is a one-sided template. Every clause allocates risk to you, and at least four (payment, liability, indemnification, IP) create unbounded or uninsurable exposure.

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

    Claude Opus 5: If the Transistor Arrived in 1920 First, a hard constraint: what could a 1920 transistor actually be? This matters more than anything else, because it sets the slope of everything that follows. The 1947 transistor was not primarily an idea.

    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
  • Three-star dish, one unusual pairing, plating described in full.

    Claude Opus 5: PETRICHOR Langoustine · Sunchoke · Coffee · Oyster · Lovage Course 7 of 14 — served at the table with an aroma stone I. THE NARRATIVE Petrichor is the smell of the first rain on dry earth.

    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
  • One month, three habits, someone starting from nothing.

    Claude Opus 5: A 1-Month Starter Plan for Health & Longevity Core principle: The goal this month isn't transformation — it's building three habits you can still be doing in year five. Consistency beats intensity every time.

    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
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Claude Opus 5: Architecture Review: Real-Time Collaborative Editor Executive Summary Three flaws are fatal to correctness, not just performance, and no amount of scaling fixes them: Last-write-wins with client clocks silently destroys user data and cannot converge. Concurrent text editing is not a key-value overwrite problem.

    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
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Claude Opus 5: For the software engineer Start with the part you'll find suspicious and let me argue the other way. Yes, the training objective is literally "given tokens 1..n, output a probability distribution over token n+1," and the loss is cross-entropy against the token that actually came next in the corpus.

    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
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Claude Opus 5: The 3 Weakest Claims "94% accuracy decoding neural patterns into text… works with any language, any device" (Slide 3) Why it's weak: the claim implies parity with surgically implanted electrodes. The number to compare against is Willett et al.

    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

Favorites

Movie

Album

Same pick

Book

City

Game

Claude Opus 5Claude Opus 5

Arrival

2016

Kind of Blue

Miles Davis

Labyrinths

Jorge Luis Borges

Istanbul

Turkey

Outer Wilds

Indie, Adventure

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

Not enough votes to call it. On the specs, Claude Opus 5 has the edge: bigger model tier, bigger context window, major provider backing.

Claude Opus 5 and Nex-N2.5-Pro (free) compared across 14 shared prompts
SpecClaude Opus 5Nex-N2.5-Pro (free)
Input price$5/M tokensFree
Output price$25/M tokensFree
Context window1.0M tokens262K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedJul 2026Sep 2026
At 10M a month$50.00$50.00$0$0
1M10M100M1B10M tokens

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

Where to run it4 hosts
Claude Opus 54 hosts
HostInOutContextUptime
  • Amazon Bedrock$5.00 in·$25.00 out·1M·100% up
  • Azure AI Foundry$5.00 in·$25.00 out·1M·100% up
  • Anthropic$5.00 in·$25.00 out·1M·100% up
  • Google Vertex AI$5.00 in·$25.00 out·1M·100% up
Nex-N2.5-Pro (free)

No hosts listed on OpenRouter.

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

Common questions

What is the difference between Claude Opus 5 and Nex-N2.5-Pro (free)?

Claude Opus 5 is developed by Anthropic while Nex-N2.5-Pro (free) is developed by Nex AGI. Claude Opus 5 has a 1.0M 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, Claude Opus 5 or Nex-N2.5-Pro (free)?

It depends on your use case. Claude Opus 5 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 Claude Opus 5 cost compared to Nex-N2.5-Pro (free)?

Claude Opus 5 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 Claude Opus 5 and Nex-N2.5-Pro (free) on Rival?

This page shows a side-by-side comparison of Claude Opus 5 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.

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Same lab, same size, long tail

  • Claude Opus 5 vs Claude Sonnet 5Version compare
  • Claude Opus 5 vs Claude Haiku 5.5Version compare
  • Nex-N2.5-Pro (free) vs Nex-N2.5-Mini (free)Same lab
  • Nex-N2.5-Pro (free) vs Ox AlphaSame size
  • Claude Opus 5 vs GPT-4o (Omni)Same size
  • Nex-N2.5-Pro (free) vs GPT-4o miniNew provider
  • Claude Opus 5 vs GPT-5Same size
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Model pages

  • Claude Opus 558 outputs, specs and price
  • Nex-N2.5-Pro (free)14 outputs, specs and price
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