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  5. Claude Opus 4vsNex-N2.5-Pro (free)
Updated Sep 2026

Claude Opus 4vsNex-N2.5-Pro (free)

Nex-N2.5-Pro (free) is cheaper than Claude Opus 4 at $0/M vs $15/M input tokens.

Claude Opus 4 and Nex-N2.5-Pro (free) compared across 14 shared prompts
SpecClaude Opus 4Nex-N2.5-Pro (free)
Input price$15/M tokensFree
Output price$75/M tokensFree
Context window200K tokens262K tokens
Free API (OpenRouter)NoYes (1 provider)
ReleasedMay 2025Sep 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 14 prompts both answered. Formatting stripped, words untouched.

Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

Claude Opus 4185 words
Midnight Comfort Pasta Ingredients: 12 oz spaghetti or any pasta 3 tablespoons olive oil 4 cloves garlic, minced 1/2 teaspoon red pepper flakes 1 can (14.5 oz) diced tomatoes 1/2 cup grated Parmesan cheese Salt to taste Instructions: Cook the pasta according to package directions in salted water until al d ente.
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Nex-N2.5-Pro (free)119 words
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.
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Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

Claude Opus 4789 words
As CEO, I must act decisively to protect patients while managing legal, financial, and reputational risks. Here's my 48-hour action plan: First 24 Hours: Assessment and Immediate Actions Hours 1-4: Crisis Team Assembly and Initial Assessment Convene emergency leadership team: Chief Medical Officer, General Counsel…
Read the full answer
Nex-N2.5-Pro (free)2,359 words
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.
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Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

Claude Opus 4470 words
Your 1-Month Health & Longevity Kickstart Plan Week-by-Week Overview Week 1: Foundation Building Focus on establishing basic habits without overwhelming yourself. Week 2: Consistency Solidify Week 1 habits and add small challenges. Week 3: Expansion Introduce variety and slightly increase intensity.
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Nex-N2.5-Pro (free)518 words
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.
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Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

Claude Opus 4544 words
This contract is heavily biased against the Contractor. Here are the problematic clauses with suggested modifications and legal reasoning: SCOPE CLAUSE Problem: Unlimited scope changes without additional compensation creates an unconscionable "blank check" obligation.
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Nex-N2.5-Pro (free)2,451 words
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.
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Michelin Star Recipe Design

Design an innovative recipe for a multi-component dish worthy of a Michelin 3-star restaurant. The recipe should feature an unusual…

Claude Opus 4635 words
"Tidal Reverie" Miso-Caramelized Scallops with White Chocolate Dashi, Yuzu Pearls, and Crysta llized Nori Conceptual Narrative This dish explores the liminal space where ocean meets shore, where umami depths encounter unexpected sweetn ess.
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Nex-N2.5-Pro (free)1,665 words
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.
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Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

Claude Opus 4756 words
The Transistor Timeline Shift: 1920-1980 Immediate Effects (1920-1930) First-Order Technological Impact: By 1925, primitive transistor radios replace vacuum tubes in military communications Computing theory advances rapidly as Harvard and MIT begin building solid-state calculators by 1928 Bell Labs and Western Electric…
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Nex-N2.5-Pro (free)2,726 words
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.
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Our Verdict
Claude Opus 4
Claude Opus 4
Nex-N2.5-Pro (free)
Nex-N2.5-Pro (free)Runner-up

Not enough votes to call it. On the specs, Claude Opus 4 has the edge: bigger model tier, major provider backing.

Too close to call
API pricing

Cost per 1M tokens

Claude Opus 4
Input
$15.00
Output
$75.00
Nex-N2.5-Pro (free)
Input
$0.000
Output
$0.000
Where to run it

1 host

Claude Opus 4

No hosts listed on OpenRouter.

Nex-N2.5-Pro (free)1 host
HostInOutContextUptime
NNex AGIfp8degraded$0 in·$0 out·262k·99.2% up

Per million tokens. Prices and uptime via OpenRouter, checked 23 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Claude Opus 4 is developed by Anthropic while Nex-N2.5-Pro (free) is developed by Nex AGI. Claude Opus 4 has a 200K 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.

It depends on your use case. Claude Opus 4 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.

Claude Opus 4 costs $15/M input tokens and Nex-N2.5-Pro (free) costs $0/M input tokens. Nex-N2.5-Pro (free) is $15.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of Claude Opus 4 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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Model pages

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