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  5. GPT-5.3-CodexvsLaguna S 2.1 (free)
Updated Jul 2026

GPT-5.3-CodexvsLaguna S 2.1 (free)

Laguna S 2.1 (free) is cheaper than GPT-5.3-Codex at $0/M vs $1.75/M input tokens.

GPT-5.3-Codex and Laguna S 2.1 (free) compared across 10 shared prompts
SpecGPT-5.3-CodexLaguna S 2.1 (free)
Input price$1.75/M tokensFree
Output price$14/M tokensFree
Context window400K tokens262K tokens
WeightsClosed—
Free API (OpenRouter)NoYes (1 provider)
ReleasedFeb 2026Jul 2026
Side by side

Same prompt, both answers

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

Advanced Longevity Plan (Biohacker)

Develop a comprehensive, cutting-edge 3-month longevity plan for a biohacker aiming to optimize longevity, physical and cognitive…

GPT-5.3-Codex485 words
Absolutely—great goal. Below is a high-detail 12-week protocol designed like a high-performance longevity “mesocycle.” I’ll keep it practical, measurable, and advanced—but still safe. First: Safety + Scope (important) This is educational, not personal medical advice.
Read the full answer
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…
Read the full answer

Adversarial Contract Review

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

GPT-5.3-Codex1,360 words
Great prompt. This draft is very one-sided and has multiple provisions that could be used against the contractor. Quick note: I’m not a lawyer, and enforceability depends on jurisdiction. This is practical contract-risk spotting, not legal advice.
Read the full answer
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…
Read the full answer

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-5.3-Codex1,009 words
LedgerLift (LLLT) – IC Memo (Fictional) Recommendation: PASS (bias: valuation-risk skew to downside on intrinsic basis) Current Price: $46 12-mo PT range (fair value): $30–$48 (midpoint ~$38) 2-sentence thesis: LedgerLift screens as a high-quality vertical SaaS asset (92% subscription mix, 123% NRR, 6% logo churn…
Read the full answer
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.
Read the full answer
Our Verdict
GPT-5.3-Codex
GPT-5.3-Codex
Laguna S 2.1 (free)
Laguna S 2.1 (free)Runner-up

Not enough votes to call it. On the specs, GPT-5.3-Codex 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-5.3-Codex
Input
$1.75
Output
$14.00
Laguna S 2.1 (free)
Input
$0.000
Output
$0.000
Where to run it

3 hosts

GPT-5.3-Codex2 hosts
HostInOutContextUptime
Azure AI Foundry$1.75 in·$14.00 out·400k·100% upOpenAI$1.75 in·$14.00 out·400k·100% up
Laguna S 2.1 (free)1 host
HostInOutContextUptime
PPoolsidefp4$0 in·$0 out·262k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 22 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

GPT-5.3-Codex is developed by OpenAI while Laguna S 2.1 (free) is developed by Poolside. GPT-5.3-Codex has a 400K 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.

It depends on your use case. GPT-5.3-Codex 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.

GPT-5.3-Codex costs $1.75/M input tokens and Laguna S 2.1 (free) costs $0/M input tokens. Laguna S 2.1 (free) is $1.75/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-5.3-Codex 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.

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Model pages

GPT-5.3-Codex logo
GPT-5.3-Codex53 outputs, specs and price
Laguna S 2.1 (free) logo
Laguna S 2.1 (free)10 outputs, specs and price
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