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  5. GPT-5.1 Codex MaxvsNex-N2.5-Pro (free)
Updated Sep 2026

GPT-5.1 Codex MaxvsNex-N2.5-Pro (free)

Nex-N2.5-Pro (free) is the newer model, released after GPT-5.1 Codex Max.

GPT-5.1 Codex Max and Nex-N2.5-Pro (free) compared across 14 shared prompts
SpecGPT-5.1 Codex MaxNex-N2.5-Pro (free)
Input price—Free
Output price—Free
Context window—262K tokens
WeightsClosed—
Free API (OpenRouter)NoYes (1 provider)
ReleasedDec 2025Sep 2026
Side by side

Same prompt, both answers

Opening lines from 2 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…

GPT-5.1 Codex Max175 words
Sunset Chickpea & Tomato Skillet A cozy, savory one-pan dish that comes together with staples you likely have on hand. Ingredients (7): 1 can (15 oz) chickpeas, drained and rinsed 1 can (14–15 oz) crushed tomatoes 1 medium onion, finely chopped 2 cloves garlic, minced (or 1 tsp garlic powder) 2 tbsp olive oil 1 tsp…
Read the full answer
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.
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…

GPT-5.1 Codex Max386 words
Here's a simple four‑week framework to help you ease into healthier habits. It keeps the focus on three big levers you can control and builds gradually so it feels doable. Key areas: Nourishing food, regular movement, and rest/recovery.
Read the full answer
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.
Read the full answer
Our Verdict
GPT-5.1 Codex Max
GPT-5.1 Codex Max
Nex-N2.5-Pro (free)
Nex-N2.5-Pro (free)Runner-up

Not enough votes to call it. On the specs, GPT-5.1 Codex Max has the edge: bigger model tier, major provider backing.

Too close to call
API pricing

Cost per 1M tokens

GPT-5.1 Codex Max
Input
—
Output
—
Nex-N2.5-Pro (free)
Input
$0.000
Output
$0.000
Where to run it

2 hosts

GPT-5.1 Codex Max1 host
HostInOutContextUptime
Azure AI Foundry$1.25 in·$10.00 out·400k·100% up
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

GPT-5.1 Codex Max is developed by OpenAI while Nex-N2.5-Pro (free) is developed by Nex AGI. You can compare their actual outputs across 14 challenges on Rival to see how they differ in practice.

It depends on your use case. GPT-5.1 Codex Max 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.

This page shows a side-by-side comparison of GPT-5.1 Codex Max 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

GPT-5.1 Codex Max logo
GPT-5.1 Codex Max53 outputs, specs and price
Nex-N2.5-Pro (free) logo
Nex-N2.5-Pro (free)14 outputs, specs and price
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