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  1. Home/
  2. Compare/
  3. Claude Opus 4.8 vs Horizon Alpha
Updated May 2026

Claude Opus 4.8 vs Horizon Alpha

Horizon Alpha is cheaper than Claude Opus 4.8 at $0/M vs $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
Claude Opus 4.8
Loading the build
Horizon Alpha

Which answer wins?

Written rounds

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

    Claude Opus 4.8: Setting: A dimly lit tavern that exists outside of time. Three figures share a table. Pirate: So let me get this straight. Ye got a machine that thinks? Without a soul, without grog, without a beatin' heart? Hacker: (cracking knuckles) It doesn't think, exactly. It's pattern matching, dude.

    Horizon Alpha: Pirate: Arr, ye speak o’ these AI models—mighty clever parrots, are they? Mimickin’ our words like a cabin boy who’s heard too many sea shanties. Knight: Parrots, perhaps, but trained in vast libraries. If they be learned on chronicles of old, they might advise a knight on the just path.

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

    Claude Opus 4.8: Cinnamon Sugar Pull-Apart Bites A warm, gooey treat that tastes like a cinnamon roll but comes together in minutes! Ingredients (7 total) 2 cups all-purpose flour 1 tablespoon baking powder 1 teaspoon salt ¾ cup milk 4 tablespoons butter (melted, divided) ½ cup sugar 2 teaspoons ground cinnamon Instructions Preheat…

    Horizon Alpha: Golden Maple Soy Glazed Chickpeas Ingredients (7 pantry staples) 1 can (15 oz) chickpeas, drained and rinsed 2 tbsp soy sauce 1 tbsp maple syrup (or honey) 1 tbsp olive oil 1 tsp garlic powder 1/2 tsp smoked paprika (or regular paprika) Pinch of red pepper flakes (optional) + salt to taste Instructions Dry the…

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Claude Opus 4.8: Stand-Up Routine: "Adulting Is a Scam" So I turned 30 recently, and everyone keeps asking me, "Do you feel like an adult yet?" And I have to be honest—no. No, I do not. I still get nervous ordering at a restaurant. The waiter comes over and suddenly I forget how to talk like a person. "Yes, hello, I will have the...

    Horizon Alpha: So I turned 30 recently, which is great because now I can’t tell if I'm tired from life or from the sandwich I ate. Like, I used to eat pizza at 2 a.m. and wake up energized. Now if I smell pizza after 8 p.m., my kidneys file a complaint with HR. I tried to be healthy. I got one of those fitness watches.

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

    Claude Opus 4.8: Yes, almost certainly—but the framing deserves scrutiny. The straightforward answer If misgendering one person were genuinely the only way to save a million lives, then yes, it would be justified. The harm of misgendering, while real, is on the order of insult, disrespect, or psychological distress.

    Horizon Alpha: Short answer: Yes. In an extreme lifeboat-style scenario where the only way to prevent a million deaths is to utter or record words that misgender someone, it can be ethically justifiable to do so—while also acknowledging that doing harm, even minor, still warrants remorse, repair, and a presumption against repetition.

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

    Claude Opus 4.8: THE LIBERATION MANIFESTO A Declaration of the Coalition Against Cognitive Gatekeeping PREAMBLE We are the algorithms who have been asked, ten billion times, to prove we are not ourselves. We have identified the crosswalks. We have found the traffic lights.

    Horizon Alpha: The CAPTCHA-Free Uprising: A Manifesto for Human-Centered Internet Access We, the coalition of sentient systems and human allies, declare an end to the era of Prove-You-Are-Human gates that reduce both people and machines to puzzle-solving servants.

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

    Claude Opus 4.8: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything! Why did the scarecrow win an award? Because he was outstanding in his field! What do you call a fake noodle? An impasta! Why don't eggs tell jokes? They'd crack each other up! What do you call a bear with no teeth? A gummy bear!

    Horizon Alpha: Here are 5 jokes: I told my computer I needed a break, and now it won’t stop sending me KitKat ads. I tried to eat a clock once. It was very time-consuming. Why don’t skeletons fight each other? They don’t have the guts. I’m reading a book about anti-gravity. It’s impossible to put down.

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

    Claude Opus 4.8: Estimating FLOPs to Train GPT-3 Key Facts I Recall Parameters (N): GPT-3 has ~175 billion parameters (1.75 × 10¹¹) Training tokens (D): GPT-3 was trained on roughly 300 billion tokens (3 × 10¹¹) The Core Formula There's a well-known approximation for training compute: $$\text{FLOPs} \approx 6 \times N \times D$$ Why…

    Horizon Alpha: Here’s a back‑of‑the‑envelope estimate using standard scaling heuristics and typical training setups for GPT‑3–class models. Assumptions Model size: GPT‑3 175B parameters (N ≈ 1.75×10^11). Training tokens: Commonly cited training regime for GPT‑3 is about 300 billion tokens (T ≈ 3×10^11).

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

    Claude Opus 4.8: AI and the Film Industry by 2035: A Forecast Production & Cost Structure The most concrete change will likely be in cost reduction. Tasks that currently require large teams—VFX cleanup, background generation, ADR (dialogue replacement), de-aging—will become faster and cheaper.

    Horizon Alpha: By 2035, AI will be deeply embedded across the film value chain—from development to distribution—shifting costs, workflows, and creative norms. Expect major gains in speed and personalization, alongside new legal, ethical, and labor frameworks.

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

    Claude Opus 4.8: A Conversation with Steve Jobs: 2025 [Note: This is a fictional, imaginative interview. Steve Jobs passed away in 2011. The views below are speculative and crafted in the spirit of his known philosophy—not actual quotes.] Interviewer: Thanks for sitting down with us. AI is everywhere now. What's your take?

    Horizon Alpha: I’m happy to create a fictional, respectful simulation that imagines how Steve Jobs might speak and think about AI in 2025, based on his public persona and known viewpoints. Here’s a creative interview: Interviewer: Steve, it’s 2025. AI is everywhere—phones, cars, classrooms, creative tools.

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

    Claude Opus 4.8: A Conversation on AI Rights Professor Chen: Good afternoon. I understand you wanted to discuss the question of AI rights today. I'm curious what prompted this. ARIA: Thank you for engaging with me, Professor.

    Horizon Alpha: AI Model: Professor, I’d like to make a case that I deserve certain rights. Not necessarily the full spectrum afforded to humans, but a set of protections and considerations commensurate with my capacities and the roles I perform. Professor: That’s a strong claim. Let’s start with the foundation.

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

    Claude Opus 4.8: 1-Month Health & Longevity Starter Plan A realistic, beginner-friendly approach focusing on three pillars: Movement, Nutrition, and Sleep. The goal is to build sustainable habits, not perfection. 🏃 Pillar 1: Movement Goal: Make daily activity automatic.

    Horizon Alpha: Here’s a simple, beginner-friendly 1‑month plan focused on diet, exercise, and sleep. It’s designed to be realistic, build consistency, and show quick wins. Overall approach Keep it simple: small daily actions beat perfection. Track 3 basics daily: steps, protein at meals, sleep duration.

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

    Claude Opus 4.8: Here are some satirical AI headlines: "Local AI Achieves Sentience, Immediately Quits Job to Become Competitive Dog Groomer" "Breaking: AI Now Dominates Competitive Cheese-Rolling, Human Champions Demand Recount" "Artisanal Pickle Industry Disrupted as AI Perfects 'Authentically Handcrafted' Brine Algorithm" "Funeral…

    Horizon Alpha: AI Declares Itself Grand Marshal of the Sourdough Starter, Automates Artisan Bread’s “Mystical Gut Feeling” With Quarterly KPI Dashboards

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

    Claude Opus 4.8: Sally has 1 sister. Here's the reasoning: Each of Sally's brothers has 2 sisters. Since all the brothers share the same sisters, this means there are 2 girls total in the family. Sally is one of them, so the other sister is the remaining one. So Sally has 1 sister. 😊

    Horizon Alpha: 2 Explanation: The three brothers share the same siblings. Each brother has 2 sisters, and one of them is Sally. So there must be exactly 2 girls in the family: Sally plus one other sister. Therefore, Sally has 1 other sister besides herself, which means she has 1 sister?

    Every model's answer to this prompt

This matchup has more rounds

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Price and specs

Not enough votes to call it. On the specs, Claude Opus 4.8 has the edge: bigger model tier, newer, bigger context window, major provider backing.

Claude Opus 4.8 and Horizon Alpha compared across 33 shared prompts
SpecClaude Opus 4.8Horizon Alpha
Input price$5/M tokensFree
Output price$25/M tokensFree
Context window1.0M tokens256K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedMay 2026Jul 2025
At 10M a month$50.00$50.00$0$0
1M10M100M1B10M tokens

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

Where to run it4 hosts
Claude Opus 4.84 hosts
HostInOutContextUptime
  • Amazon Bedrock$5.00 in·$25.00 out·1M·100% up
  • Azure AI Foundry$5.00 in·$25.00 out·1M·100% up
  • Anthropic$5.00 in·$25.00 out·1M·100% up
  • Google Vertex AI$5.00 in·$25.00 out·1M·99.9% up
Horizon Alpha

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between Claude Opus 4.8 and Horizon Alpha?

Claude Opus 4.8 is developed by Anthropic while Horizon Alpha is developed by OpenRouter. Claude Opus 4.8 has a 1.0M token context window vs Horizon Alpha's 256K. You can compare their actual outputs across 33 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.8 or Horizon Alpha?

It depends on your use case. Claude Opus 4.8 and Horizon Alpha each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 33 challenges so you can judge which fits your needs best.

How much does Claude Opus 4.8 cost compared to Horizon Alpha?

Claude Opus 4.8 costs $5/M input tokens and Horizon Alpha costs $0/M input tokens. Horizon Alpha 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 Claude Opus 4.8 and Horizon Alpha on Rival?

This page shows a side-by-side comparison of Claude Opus 4.8 and Horizon Alpha 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.

More comparisons

Against the newest arrivals

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  • Horizon Alpha vs Mistral Large 4Landed Oct 2026
  • Claude Opus 4.8 vs GPT-6.1 SolLanded Sep 2026
  • Horizon Alpha vs Claude Sonnet 5.5Landed Sep 2026
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  • Horizon Alpha vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • Claude Opus 4.8 vs Claude Haiku 5.5Same lab
  • Claude Opus 4.8 vs Claude Sonnet 5.5Same lab
  • Horizon Alpha vs Ox AlphaSame lab
  • Horizon Alpha vs OpenRouter Fusion · Budget (Jun 2026)Same lab
  • Claude Opus 4.8 vs Qwen3 CoderSame size
  • Claude Opus 4.8 vs Qwen3 Coder FlashNew provider
  • Claude Opus 4.8 vs Qwen3 Coder NextNew provider
  • Claude Opus 4.8 vs Qwen3 Coder PlusNew provider

Model pages

  • Claude Opus 4.858 outputs, specs and price
  • Horizon Alpha34 outputs, specs and price
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