What is the difference between GPT-5.5 and Laguna S 2.1 (free)?

GPT-5.5 is developed by OpenAI while Laguna S 2.1 (free) is developed by Poolside. GPT-5.5 has a 1.1M token context window vs Laguna S 2.1 (free)'s 262K. You can compare their actual outputs across 10 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.5 or Laguna S 2.1 (free)?

It depends on your use case. GPT-5.5 and Laguna S 2.1 (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 10 challenges so you can judge which fits your needs best.

How much does GPT-5.5 cost compared to Laguna S 2.1 (free)?

GPT-5.5 costs $5/M input tokens and Laguna S 2.1 (free) costs $0/M input tokens. Laguna S 2.1 (free) is $5.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare GPT-5.5 and Laguna S 2.1 (free) on Rival?

This page shows a side-by-side comparison of GPT-5.5 and Laguna S 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.

Updated Jul 2026

GPT-5.5vsLaguna S 2.1 (free)

Laguna S 2.1 (free) is cheaper than GPT-5.5 at $0/M vs $5/M input tokens.

GPT-5.5 and Laguna S 2.1 (free) compared across 10 shared prompts
Spec	GPT-5.5	Laguna S 2.1 (free)
Input price	$5/M tokens	Free
Output price	$30/M tokens	Free
Context window	1.1M tokens	262K tokens
Weights	Closed	—
Free API (OpenRouter)	No	Yes (1 provider)
Released	Apr 2026	Jul 2026

Side by side

Same prompt, both answers

Opening lines from 3 of the 10 prompts both answered. Formatting stripped, words untouched.

Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

GPT-5.52,391 words

Not legal advice; contract enforceability depends heavily on jurisdiction and facts. A contractor should have a lawyer review this before signing. That said, this draft is heavily one-sided and contains multiple clauses that could be exploited against the contractor.

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Laguna S 2.1 (free)275 words

I'll analyze each clause for potential exploitation against the contractor and suggest improvements. Exploitable Clauses & Recommended Modifications SCOPE CLAUSE Problem: "Client reserves the right to modify the scope at any time without additional compensation" Allows unlimited scope creep without extra pay No…

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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…

GPT-5.52,734 words

Below is a 12-week longevity + performance plan designed for a healthy adult biohacker. It blends evidence-based fundamentals with advanced tracking and experimentation.

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Laguna S 2.1 (free)1,140 words

Comprehensive 3-Month Longevity Optimization Plan Phase 1: Foundation & Assessment (Month 1) Week 1-2: Baseline Establishment Comprehensive Health Testing Complete blood panel (CBC, CMP, lipid panel, inflammatory markers: hs-CRP, IL-6) Hormone panel (testosterone, estrogen, DHEA, cortisol, thyroid panel) Genetic…

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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-5.51,055 words

LedgerLift (LLLT) IC Memo — Fictional Recommendation: Pass / Watchlist Current price: $46 Market cap: $8.7B; EV: $7.3B after $1.4B net cash 12-month fair value range: $40–$50/share Thesis, 2 sentences: LedgerLift is a high-quality mid-market spend management/AP automation SaaS asset with 92% subscription revenue, 123%…

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Laguna S 2.1 (free)910 words

INTERNAL INVESTMENT COMMITTEE MEMO 1. Recommendation & Thesis Recommendation: LONG 12-Month Price Target Range: $62 – $75/share Thesis: LedgerLift is a high-quality B2B SaaS platform with strong recurring revenue, exceptional unit economics, and durable customer retention.

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Our Verdict

GPT-5.5

Laguna S 2.1 (free)Runner-up

Not enough votes to call it. On the specs, GPT-5.5 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-5.5

Input

$5.00

Output

$30.00

Laguna S 2.1 (free)

Input

$0.000

Output

$0.000

Where to run it

4 hosts, cheapest first

GPT-5.53 hosts

HostInOutContextUptime

Azure AI Foundry$5.00 in$30.00 out1.1M100% up OpenAI$5.00 in$30.00 out1.1M100% up Amazon Bedrock$5.50 in$33.00 out1.1M—

Laguna S 2.1 (free)1 host

HostInOutContextUptime

Poolsidefp4$0 in$0 out262k100% up

Per million tokens. Prices and uptime via OpenRouter, checked 23 Sep 2026.

Research

What we learned reading every model

FAQ

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