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

GPT-5.1vsLaguna XS 2.1 (free)

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

GPT-5.1 and Laguna XS 2.1 (free) compared across 11 shared prompts
SpecGPT-5.1Laguna XS 2.1 (free)
Input price$1.25/M tokensFree
Output price$10/M tokensFree
Context window400K tokens262K tokens
WeightsClosed—
Free API (OpenRouter)NoYes (1 provider)
ReleasedNov 2025Jul 2026
Our Verdict
GPT-5.1
GPT-5.1
Laguna XS 2.1 (free)
Laguna XS 2.1 (free)Runner-up

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

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

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

3 hosts

GPT-5.12 hosts
HostInOutContextUptime
Azure AI Foundry$1.25 in·$10.00 out·400k·100% upOpenAI$1.25 in·$10.00 out·400k·100% up
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 is developed by OpenAI while Laguna XS 2.1 (free) is developed by Poolside. GPT-5.1 has a 400K 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 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 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 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.

Keep exploring

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Model pages

GPT-5.1 logo
GPT-5.152 outputs, specs and price
Laguna XS 2.1 (free) logo
Laguna XS 2.1 (free)11 outputs, specs and price
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