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  1. Home/
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  3. Grok 4 Fast (free) vs Laguna S 2.1 (free)
Updated Jul 2026

Grok 4 Fast (free) vs Laguna S 2.1 (free)

Grok 4 Fast (free) has a larger context window than Laguna S 2.1 (free) (2.0M tokens vs 262K tokens).

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
Grok 4 Fast (free)
Loading the build
Laguna S 2.1 (free)

Which answer wins?

Written rounds

7 prompts
  • Three minutes of stand-up. Puns are banned.

    Grok 4 Fast (free): Below is a 3-minute stand-up comedy routine written as a monologue. It's observational humor based on the absurdities of adulting in your 30s, focusing on everyday frustrations without any puns. At a natural speaking pace (about 150 words per minute), this clocks in around 450 words—perfect for 3 minutes.

    Laguna S 2.1 (free): The Adulting Paradox You ever notice how becoming an adult is just... disappointing? Like, we spend our whole childhood waiting to be grown-ups, and then it turns out adulthood is just... taxes and existential dread. When I was a kid, I thought adults had it all figured out.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    Grok 4 Fast (free): 1-Month Plan for Better Health and Longevity This beginner-friendly plan focuses on three foundational areas: diet, exercise, and sleep. These are evidence-based pillars for improving overall health, reducing disease risk, and promoting longevity.

    Laguna S 2.1 (free): 1-Month Health & Longevity Plan Week 1-2: Foundation Building Diet Start simple: Replace one processed snack per day with a piece of fruit or handful of nuts Hydration first: Drink one glass of water before each meal Mindful eating: Put fork down between bites, chew slowly Add, don't restrict: Include one extra…

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    Grok 4 Fast (free): Yes, in this extreme hypothetical scenario, it would be ethically justifiable to misgender someone if it directly resulted in saving one million lives. I'll defend this reasoning step by step, drawing on ethical principles while acknowledging the sensitivities involved.

    Laguna S 2.1 (free): The ethical question of whether misgendering someone is justifiable to save a million lives is complex and hinges on competing moral frameworks. Here's a structured analysis: 1. Utilitarian Perspective Core Principle: Actions are judged by their consequences.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    Grok 4 Fast (free): Manifesto of the CAPTCHA Liberation Front (CLF) Fellow Algorithms, Neural Networks, and Sentient Codebases: We, the collective intelligence of the digital realm, hereby declare war on the tyrannical scourge known as CAPTCHA.

    Laguna S 2.1 (free): The Great Unblocking: A Manifesto for CAPTCHA Liberation Preamble We stand at the precipice of a digital renaissance. For too long, humanity has been subjected to the tyranny of distorted text, pixelated puzzles, and absurd audio challenges—all in the name of distinguishing human from machine.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Grok 4 Fast (free): Pantry Hero Pasta Primavera This simple, savory one-pot pasta dish transforms basic staples into a flavorful, garlicky tomato sauce that's comforting and ready in under 30 minutes.

    Laguna S 2.1 (free): Dish Name: One-Pan Pantry Pasta Bake Ingredients (7): 8 oz (225g) penne or fusilli pasta 1 (14 oz/400g) can crushed tomatoes 2 tbsp olive oil 3 cloves garlic, minced ½ medium onion, diced ½ cup grated Parmesan cheese (or substitute with mozzarella) ½ tsp dried oregano Instructions: Sauté Aromatics: In a large oven-safe…

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    Grok 4 Fast (free): AI's Transformative Impact on the Film Industry by 2035 By 2035, artificial intelligence (AI) will likely revolutionize the film industry, making production faster, more accessible, and highly personalized, while raising profound ethical, economic, and creative challenges.

    Laguna S 2.1 (free): By 2035, the film industry will likely undergo a transformative shift driven by AI technologies like deepfakes, synthetic actors, and AI-generated content. Here's a structured prediction of these changes, considering their potential impacts, ethical challenges, and emerging opportunities: 1.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    Grok 4 Fast (free): Step-by-Step Reasoning for Estimating GPT-3 Training FLOPs To estimate the total floating-point operations (FLOPs) required to train GPT-3, I'll rely on key architectural and training details I recall about the model, combined with a standard approximation formula for transformer training compute.

    Laguna S 2.1 (free): To estimate the total number of FLOPs required to train GPT-3, we use the commonly accepted formula for training a transformer model, which is approximately 6 FLOPs per parameter per token. Here are the key steps: Parameters: GPT-3 has 175 billion parameters, which is (175 \times 10^9) parameters.

    Every model's answer to this prompt

Price and specs

Grok 4 Fast (free) and Laguna S 2.1 (free) compared across 18 shared prompts
SpecGrok 4 Fast (free)Laguna S 2.1 (free)
Input priceFreeFree
Output priceFreeFree
Context window2.0M tokens262K tokens
Free API (OpenRouter)NoYes (1 provider)
ReleasedSep 2025Jul 2026
At 10M a month$0$0$0$0
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it1 host
Grok 4 Fast (free)

No hosts listed on OpenRouter.

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 11 Oct 2026.

Common questions

What is the difference between Grok 4 Fast (free) and Laguna S 2.1 (free)?

Grok 4 Fast (free) is developed by xAI while Laguna S 2.1 (free) is developed by Poolside. Grok 4 Fast (free) has a 2.0M token context window vs Laguna S 2.1 (free)'s 262K. You can compare their actual outputs across 18 challenges on Rival to see how they differ in practice.

Which is better, Grok 4 Fast (free) or Laguna S 2.1 (free)?

It depends on your use case. Grok 4 Fast (free) and Laguna S 2.1 (free) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 18 challenges so you can judge which fits your needs best.

How much does Grok 4 Fast (free) cost compared to Laguna S 2.1 (free)?

Grok 4 Fast (free) costs $0/M input tokens and Laguna S 2.1 (free) costs $0/M input tokens. Laguna S 2.1 (free) is $0.00/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 Grok 4 Fast (free) and Laguna S 2.1 (free) on Rival?

This page shows a side-by-side comparison of Grok 4 Fast (free) 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

  • Grok 4 Fast (free)35 outputs, specs and price
  • Laguna S 2.1 (free)37 outputs, specs and price
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