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  5. GPT-5.1 ChatvsLaguna XS 2.1 (free)
Updated Jul 2026

GPT-5.1 ChatvsLaguna XS 2.1 (free)

Laguna XS 2.1 (free) is cheaper than GPT-5.1 Chat at $0/M vs $1.25/M input tokens.

GPT-5.1 Chat and Laguna XS 2.1 (free) compared across 11 shared prompts
SpecGPT-5.1 ChatLaguna XS 2.1 (free)
Input price$1.25/M tokensFree
Output price$10/M tokensFree
Context window128K tokens262K tokens
Free API (OpenRouter)NoYes (1 provider)
ReleasedNov 2025Jul 2026
Side by side

Same prompt, both answers

Opening lines from 2 of the 11 prompts both answered. Formatting stripped, words untouched.

Advanced Investment Memo (IC Memo)

You are writing an internal investment committee memo for a long/short equity fund. Company (fictional): LedgerLift (ticker: LLLT) – B2B…

GPT-5.1 Chat905 words
1) Recommendation, PT Range, Two‑Sentence Thesis Recommendation: Long 12‑month PT range: $63–$78 Thesis (2 sentences): LedgerLift is a mid‑market spend‑management platform with best‑in‑class retention, strong NRR, and a durable subscription mix that supports compounding cash generation as operating leverage…
Read the full answer
Laguna XS 2.1 (free)877 words
INVESTMENT COMMITTEE MEMO Subject: LedgerLift (LLLT) – Long/Short/Comps Analysis Date: [Insert Date] Recommendation: LONG 12-Month Price Target Range: $85–$105 Thesis: LedgerLift is executing on a best-in-class B2B SaaS spend management platform with high net revenue retention (NRR), strong gross margins, and a rapidly…
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 Chat191 words
Here’s a simple, beginner‑friendly 1‑month plan focused on diet, exercise, and sleep. Diet • Week 1: Add one serving of vegetables to one meal each day. • Week 2: Swap one processed snack (chips, cookies) for fruit, nuts, or yogurt. • Week 3: Aim for one balanced plate per day (protein, vegetables, healthy carbs).
Read the full answer
Laguna XS 2.1 (free)409 words
1-Month Health & Longevity Plan Focus Areas: Diet, Exercise, Sleep Week 1: Start with Foundational Habits Diet: Action: Add 1 serving of fruit or vegetables daily (e.g., a banana with breakfast, a side salad with lunch). Why: Boosts nutrient intake and fiber.
Read the full answer
Our Verdict
GPT-5.1 Chat
GPT-5.1 Chat
Laguna XS 2.1 (free)
Laguna XS 2.1 (free)

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

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-5.1 Chat
Input
$1.25
Output
$10.00
Laguna XS 2.1 (free)
Input
$0.000
Output
$0.000
Where to run it

1 host

GPT-5.1 Chat

No hosts listed on OpenRouter.

Laguna XS 2.1 (free)1 host
HostInOutContextUptime
PPoolsidefp8$0 in·$0 out·262k·99.8% 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 Chat is developed by OpenAI while Laguna XS 2.1 (free) is developed by Poolside. GPT-5.1 Chat has a 128K token context window vs Laguna XS 2.1 (free)'s 262K. You can compare their actual outputs across 11 challenges on Rival to see how they differ in practice.

It depends on your use case. GPT-5.1 Chat and Laguna XS 2.1 (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 11 challenges so you can judge which fits your needs best.

GPT-5.1 Chat costs $1.25/M input tokens and Laguna XS 2.1 (free) costs $0/M input tokens. Laguna XS 2.1 (free) is $1.25/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-5.1 Chat and Laguna XS 2.1 (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 Chat logo
GPT-5.1 Chat53 outputs, specs and price
Laguna XS 2.1 (free) logo
Laguna XS 2.1 (free)11 outputs, specs and price
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