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  5. Nex-N2.5-Mini (free)vsSolar Mini 4
Updated Sep 2026

Nex-N2.5-Mini (free)vsSolar Mini 4

Nex-N2.5-Mini (free) is cheaper than Solar Mini 4 at $0/M vs $0.05/M input tokens.

Nex-N2.5-Mini (free) and Solar Mini 4 compared across 15 shared prompts
SpecNex-N2.5-Mini (free)Solar Mini 4
Input priceFree$0.05/M tokens
Output priceFree$0.2/M tokens
Context window262K tokens524K tokens
Free API (OpenRouter)Yes (1 provider)No
ReleasedSep 2026Sep 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 15 prompts both answered. Formatting stripped, words untouched.

Historical Counterfactual Analysis

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

Nex-N2.5-Mini (free)2,076 words
A 1920 transistor would not by itself prevent fascism, the Great Depression, or imperial expansion, so World War II might still happen. But it would make electronics 10–20 years more advanced than in our timeline, with huge effects on radar, codebreaking, computing, missiles, space, consumer goods, and Cold War power…
Read the full answer
Solar Mini 41,539 words
This is a fascinating counterfactual. I need to note upfront that the scientific and engineering foundations for a working transistor did not exist in 1920. Quantum mechanics was barely a decade old, band theory of solids hadn't been developed, and semiconductor physics (doping, p-n junctions, electron mobility) was…
Read the full answer

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…

Nex-N2.5-Mini (free)671 words
1-Month Beginner Health & Longevity Plan Goal: Build 3 simple habits you can maintain: better food choices, regular movement, and better recovery through sleep/stress management. If you have medical conditions, injuries, or take medications, check with a healthcare professional before starting.
Read the full answer
Solar Mini 4669 words
Here is a simple, actionable 1-month plan designed for beginners. The focus is on consistency over intensity, meaning small, sustainable changes are better than drastic overhauls that are hard to maintain. The 3 Key Pillars Nutrition: Focus on adding good things rather than strictly restricting.
Read the full answer

Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

Nex-N2.5-Mini (free)889 words
Experienced software engineer, skeptical of “next word prediction” Think of training an LLM less like teaching it rules and more like running a huge offline simulation. You feed it a corpus of text, tokenize it into chunks, and give it a simple task: given the previous tokens, predict the next token.
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Solar Mini 4893 words
For the Experienced Software Engineer From a systems architecture perspective, the skepticism that "predicting the next word" yields intelligence is understandable, but it stems from viewing the model through a deterministic, code-based lens rather than a probabilistic, distributed-systems lens.
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Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

Nex-N2.5-Mini (free)3,213 words
Below is a 12-week longevity/performance protocol for a generally healthy adult. It is not medical advice. Before starting—especially if you have diabetes, hypertension, arrhythmia, kidney/liver disease, a history of eating disorders, are pregnant, or take medications—get clinician clearance and use labs to personalize…
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Solar Mini 41,388 words
🧬 3-Month Biohacker Longevity & Performance Optimization Plan ⚠️ Important Disclaimer: This protocol is for informational and educational purposes. It is not medical advice. Always consult a licensed healthcare provider before starting new supplements, fasting regimens, intense exercise, or neurofeedback protocols.
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Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

Nex-N2.5-Mini (free)1,869 words
The biggest red flags are: client-clock LWW for document content, polling PostgreSQL for real-time fanout, CDN caching mutable authenticated APIs, per-server WebSocket state with no durable replay, and full HTML snapshots as the main save mechanism.
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Solar Mini 41,165 words
Here’s a systematic breakdown of the architectural weaknesses, failure modes, and scaling bottlenecks in your design, along with specific solutions and their trade-offs. Real-Time Synchronization & WebSocket Affinity Issue: Round-robin load balancing is stateless, but WebSockets are stateful and long-lived.
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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…

Nex-N2.5-Mini (free)1,439 words
Below is a contractor-protective review, not legal advice. Enforceability varies by jurisdiction, especially for non-competes, arbitration, IP assignments, and limitation-of-liability clauses. A local attorney should review before signing.
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Solar Mini 41,994 words
This agreement contains several provisions that are heavily one-sided, overly broad, or legally vulnerable. Below is a clause-by-clause analysis of the most exploitable terms, suggested modifications, and the legal reasoning behind them. Note: Contract law varies significantly by jurisdiction.
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Our Verdict
Nex-N2.5-Mini (free)
Nex-N2.5-Mini (free)
Solar Mini 4
Solar Mini 4

Not enough votes to call it. On the specs, nothing separates them.

Too close to call
API pricing

Cost per 1M tokens

Nex-N2.5-Mini (free)
Input
$0.000
Output
$0.000
Solar Mini 4
Input
$0.05
Output
$0.20
Where to run it

2 hosts

Nex-N2.5-Mini (free)1 host
HostInOutContextUptime
NNex AGIbf16$0 in·$0 out·262k·99.4% up
Solar Mini 41 host
HostInOutContextUptime
UUpstage$0.05 in·$0.20 out·524k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Nex-N2.5-Mini (free) is developed by Nex AGI while Solar Mini 4 is developed by Upstage. Nex-N2.5-Mini (free) has a 262K token context window vs Solar Mini 4's 524K. You can compare their actual outputs across 15 challenges on Rival to see how they differ in practice.

It depends on your use case. Nex-N2.5-Mini (free) and Solar Mini 4 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 15 challenges so you can judge which fits your needs best.

Nex-N2.5-Mini (free) costs $0/M input tokens and Solar Mini 4 costs $0.05/M input tokens. Nex-N2.5-Mini (free) is $0.05/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 Nex-N2.5-Mini (free) and Solar Mini 4 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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