Nex-N2.5-Mini (free) is cheaper than GPT-6.1 Sol at $0/M vs $2/M input tokens.
Seven pantry ingredients, one dish, and a name worth saying out loud.
GPT-6.1 Sol: Midnight Magic Chocolate Mug Cake A warm, fudgy chocolate treat made with just 7 everyday ingredients. Serves: 1 Prep: 3 minutes Cook: 1–1½ minutes Rest: 1 minute Ingredients 4 tablespoons all-purpose flour 2 tablespoons sugar 1 tablespoon unsweetened cocoa powder ¼ teaspoon baking powder A small pinch of salt 3…
Nex-N2.5-Mini (free): Golden Peanut Lantern Noodles Time: Prep 5 min Cook 10 min Serves: 2 Ingredients — 7 pantry staples Spaghetti or any noodles Peanut butter Soy sauce Honey Garlic powder Rice vinegar Water Instructions Cook the noodles: Boil noodles in water until tender. Reserve about ½ cup cooking water, then drain.
A collaborative editor that syncs on client clocks. Find what breaks first.
GPT-6.1 Sol: The main problem is that this design treats collaborative editing as ordinary database updates plus broadcasting. Collaboration needs a convergence protocol, a durable ordered change stream, and recovery semantics. Adding servers alone will not provide those properties.
Nex-N2.5-Mini (free): 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.
Three-month biohacker protocol, with dosages and biomarkers named.
GPT-6.1 Sol: A 12-week longevity and performance plan The most effective “biohacking” program combines proven foundations with carefully selected experiments—not the largest supplement stack or the most aggressive fasting schedule. This plan is for a generally healthy adult.
Nex-N2.5-Mini (free): 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…
A consulting contract with traps in it. Find them, then fix them.
GPT-6.1 Sol: This agreement is heavily weighted toward the Client. Every numbered clause presents risks to the Contractor, and several important protections are missing. This is general contract analysis, not legal advice.
Nex-N2.5-Mini (free): 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.
Three-star dish, one unusual pairing, plating described in full.
GPT-6.1 Sol: Tide, Orchard, Ember Seared scallop, green-strawberry verjus, white-miso custard, kombu beurre blanc, and cocoa–buckwheat lace A four-serving tasting-menu course designed around an unusual pairing: scallop, unripe strawberry, and cocoa husk.
Nex-N2.5-Mini (free): Dish: “Nocturne in Green” — Miso-Cured Turbot, Black Garlic, Green Olive, Oak-Smoked Pear, and Black Carrot Caviar Conceptual narrative: A moonlit orchard beside a cold northern sea.
One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.
GPT-6.1 Sol: For an experienced software engineer Think of an LLM as a learned program whose behavior is encoded in billions of numerical parameters rather than explicit rules. Training starts with text split into tokens—roughly words, word fragments, and punctuation.
Nex-N2.5-Mini (free): 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.
The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.
GPT-6.1 Sol: The likeliest outcome is not “the world of 1980 arrives in 1953.” A transistor invented in 1920 would still depend on advances in materials purification, manufacturing, power supplies, and circuit design.
Nex-N2.5-Mini (free): 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…
One month, three habits, someone starting from nothing.
GPT-6.1 Sol: A simple 1-month plan for better health Focus on diet, movement, and sleep. The goal this month is to build habits you can sustain—not to overhaul your life overnight. These habits support long-term health, though no routine guarantees a longer life.
Nex-N2.5-Mini (free): 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.
A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.
GPT-6.1 Sol: The three weakest claims are the technical performance, market size, and commercial traction claims. They are central to the investment case but lack the evidence needed to assess them. “Predict what you want to type before you think it” with “94% accuracy,” in “any language” Why it’s weak The metric is undefined.
Nex-N2.5-Mini (free): The 3 weakest claims are the ones that are broadest, least falsifiable, or mathematically inconsistent. # Weak claim Why it’s weak How to strengthen it 1 “MindMeld AI reads your brainwaves to predict what you want to type before you think it.”
Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.
GPT-6.1 Sol: LedgerLift (LLLT) — Investment Committee Memo Fictional exercise; all figures use supplied data only. Financial tables are in $ millions unless noted. Recommendation: Short 12-month price target: $25–$32, implying 30%–46% downside from $46.
Nex-N2.5-Mini (free): LedgerLift (LLLT) IC Memo — Short Fictional exercise; not investment advice. $mm except per share. Recommendation Recommendation: Short. 12-month PT range: $32–$42 (midpoint ~$37), implying ~17% downside vs. current $46.
Not enough votes to call it. On the specs, GPT-6.1 Sol has the edge: bigger context window, major provider backing.
| Spec | ||
|---|---|---|
| Input price | $2/M tokens | Free |
| Output price | $10/M tokens | Free |
| Context window | 1.1M tokens | 262K tokens |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | Sep 2026 | Sep 2026 |
| At 10M a month | $20.00 | $0 |
Input tokens at list price. No caching, no batch discount.
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 6 Oct 2026.
GPT-6.1 Sol is developed by OpenAI while Nex-N2.5-Mini (free) is developed by Nex AGI. GPT-6.1 Sol has a 1.1M token context window vs Nex-N2.5-Mini (free)'s 262K. You can compare their actual outputs across 15 challenges on Rival to see how they differ in practice.
It depends on your use case. GPT-6.1 Sol and Nex-N2.5-Mini (free) 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.
GPT-6.1 Sol costs $2/M input tokens and Nex-N2.5-Mini (free) costs $0/M input tokens. Nex-N2.5-Mini (free) is $2.00/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 GPT-6.1 Sol and Nex-N2.5-Mini (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.