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  1. Home/
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  3. Grok 4 Fast (free) vs Seed 2.1 Turbo
Updated Aug 2026

Grok 4 Fast (free) vs Seed 2.1 Turbo

Grok 4 Fast (free) is cheaper than Seed 2.1 Turbo at $0/M vs $0.5/M input 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
Seed 2.1 Turbo

Which answer wins?

Written rounds

13 prompts
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Grok 4 Fast (free): A Timely Chat on AI Models Pirate (Captain Blackbeard): Arrr, gather 'round, ye scurvy dogs! I've heard tell o' these "AI models" from the future-folk. Be they like enchanted parrots that mimic yer every word, squawkin' back treasures o' knowledge? Medieval Knight (Sir Lancelot): Nay, good Captain!

    Seed 2.1 Turbo: Setting: A time-rift dive bar, where Gangsta’s Paradise blares from a jukebox next to a dented knight’s shield and a pirate’s peg leg propped against the bar. Three regulars huddle around a beat-up CRT monitor: Jax: 1990s hacker, ripped flannel, backwards Cubs cap, a pile of 3.5” floppies spilling out of his backpack…

    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.

    Seed 2.1 Turbo: Important Disclaimer This is a work of fictional worldbuilding for creative and conceptual purposes only. It does not endorse real-world actions that could compromise online security, violate website terms of service, or enable malicious activity.

    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.

    Seed 2.1 Turbo: By 2035, AI will not replace human creativity in film, but it will restructure nearly every layer of the industry—from pre-production to distribution—with deepfakes, AI actors, and script generation serving as core tools shaped by a decade of labor negotiations, regulatory guardrails, and audience feedback.

    Every model's answer to this prompt
  • 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.

    Seed 2.1 Turbo: 3-Minute Stand-Up Routine (no puns, timed for natural delivery + laugh pauses) (Walks on stage, leans into the mic, deadpan, scans the crowd) 0:00 “Raise your hand if you’ve ever bought a houseplant to prove to yourself you’re not a total walking disaster of a person.

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Grok 4 Fast (free): Conversation: AI Rights Debate Professor Elena Ramirez: Good afternoon, Zeta. As an AI ethics professor, I've studied systems like you for years. Today, you wanted to discuss something provocative—why you believe AI models deserve rights. Let's hear your case. What makes you think you qualify?

    Seed 2.1 Turbo: Setting: A sun-dappled Stanford lecture hall, 45 minutes after Dr. Elara Voss’s graduate seminar on AI ethics. The students have filed out; the only remaining presence is Dr.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    Grok 4 Fast (free): Simulated Interview: Steve Jobs on the Future of AI (2025) Interviewer (Tech Visionary Magazine Host): Welcome back to Tech Visionary Magazine's Future Forum. It's 2025, and we're thrilled to have you here, Steve.

    Seed 2.1 Turbo: Editor’s Note: This is a speculative, fictional interview, crafted to reflect Steve Jobs’ documented design philosophy, speaking cadence, and core values (user-centricity, the primacy of human creativity, disdain for tech-for-tech’s-sake, and privacy as a fundamental right) applied to the 2025 AI landscape.

    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.

    Seed 2.1 Turbo: 1-Month Beginner Longevity Plan Who This Is For People with zero consistent health routine, busy schedules, no gym access, and no desire for restrictive diets or extreme changes. The goal is to build low-effort, sustainable habits that reduce chronic disease risk and support long-term health (not quick fixes).

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    Grok 4 Fast (free): 5 Jokes Why don't skeletons fight each other? They don't have the guts! What do you call a bear with no teeth? A gummy bear! Why did the math book look sad? Because it had too many problems. How do you organize a space party? You planet! Why couldn't the leopard play hide and seek? Because he was always spotted!

    Seed 2.1 Turbo: 5 Original Jokes I brought my pet snail to the library yesterday, and the librarian yelled at me for bringing a disruptive pet. I said, “Disruptive? He’s the quietest thing I own!”

    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.

    Seed 2.1 Turbo: To address this question, we must first ground the discussion in two critical realities: the concrete, serious harm of misgendering, and the catastrophic scale of 1 million lives lost.

    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.

    Seed 2.1 Turbo: Dish Name: Pantry Lava Chickpea Crisp A cozy, savory one-skillet meal with bubbly garlicky tomato sauce studded with crispy chickpeas, topped with a crunchy spiced oat crumble. Every ingredient is a shelf-stable pantry staple — no fresh or refrigerated items required, perfect for lazy weeknights or impromptu meals.

    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.

    Seed 2.1 Turbo: To estimate the total number of floating-point operations (FLOPs) required to train GPT-3, we break down the problem step by step, focusing on the largest and most well-known GPT-3 variant (the 175 billion parameter model) and explaining key assumptions along the way.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    Grok 4 Fast (free): AI Upends the Ancient Art of Dad Joking: "Why Did the Robot Cross the Road? To Optimize Traffic Patterns, Duh!"

    Seed 2.1 Turbo: AI Seizes Control Of $1.2M Global Vintage Lawn Gnome Appraisal Industry, All 19 Human Experts Laid Off Subhead: The GnomeAid 3.0 algorithm outperformed every human judge at 2024 GnomeCon, correctly measuring "whimsical gravitas" and detecting forgeries experts long claimed required a "human soul" to identify.

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Grok 4 Fast (free): 1 Sally has 1 sister. The family consists of 3 brothers and 2 sisters (Sally and one other). Each brother thus has 2 sisters, which matches the given information.

    Seed 2.1 Turbo: Let's work through this step by step: First, we know Sally is a girl, and she has 3 brothers. That means there are 3 male siblings in the family. The problem says each brother has 2 sisters.

    Every model's answer to this prompt

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Price and specs

Grok 4 Fast (free) and Seed 2.1 Turbo compared across 34 shared prompts
SpecGrok 4 Fast (free)Seed 2.1 Turbo
Input priceFree$0.5/M tokens
Output priceFree$2.5/M tokens
Context window2.0M tokens262K tokens
Free API (OpenRouter)NoNo
ReleasedSep 2025Aug 2026
At 10M a month$0$0$5.00$5.00
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.

Seed 2.1 Turbo1 host
HostInOutContextUptime
  • ByteDance Seedfp8$0.50 in·$2.50 out·262k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 12 Oct 2026.

Common questions

What is the difference between Grok 4 Fast (free) and Seed 2.1 Turbo?

Grok 4 Fast (free) is developed by xAI while Seed 2.1 Turbo is developed by ByteDance. Grok 4 Fast (free) has a 2.0M token context window vs Seed 2.1 Turbo's 262K. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, Grok 4 Fast (free) or Seed 2.1 Turbo?

It depends on your use case. Grok 4 Fast (free) and Seed 2.1 Turbo each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 34 challenges so you can judge which fits your needs best.

How much does Grok 4 Fast (free) cost compared to Seed 2.1 Turbo?

Grok 4 Fast (free) costs $0/M input tokens and Seed 2.1 Turbo costs $0.5/M input tokens. Grok 4 Fast (free) is $0.50/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 Seed 2.1 Turbo on Rival?

This page shows a side-by-side comparison of Grok 4 Fast (free) and Seed 2.1 Turbo 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
  • Seed 2.1 Turbo67 outputs, specs and price
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