Compare Horizon Alpha by OpenRouter against Claude Opus 4 by Anthropic, in 22 community votes, horizon alpha wins 56% of head-to-head duels, context windows of 256K vs 200K, tested across 20 shared challenges. Updated April 2026.
Horizon Alpha is the better choice overall, winning 56% of 22 blind community votes on Rival. Horizon Alpha costs $0/M input tokens vs $15/M for Claude Opus 4. Context windows: 256K vs 200K tokens. Compare their real outputs side by side below.
Horizon Alpha is made by openrouter while Claude Opus 4 is from anthropic. Horizon Alpha has a 256K token context window compared to Claude Opus 4's 200K. On pricing, Horizon Alpha costs $0/M input tokens vs $15/M for Claude Opus 4. In community voting, In 22 community votes, Horizon Alpha wins 56% of head-to-head duels.
In 22 community votes, Horizon Alpha wins 56% of head-to-head duels. Horizon Alpha leads in Web Design. Based on blind community voting from the Rival open dataset of 22+ human preference judgments for this pair.
Horizon Alpha has the edge overall. In 22 blind votes, Horizon Alpha wins 56% of the time.
Horizon Alpha particularly excels in Web Design.
Claude Opus 4 uses 444.0x more bold
vsAsk them anything yourself
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
20 fights queued
Tests an AI's ability to solve a simple but potentially confusing logic puzzle
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? Wait—question asks "How many sisters does Sally have?" Since there are 2 sisters total, and one is Sally, the number of sisters Sally has is 1. Correction: The correct answer is 1.
I need to work through this step-by-step.
Given information:
Since Sally is one of the sisters that each brother has, and each brother has 2 sisters total, that means th ere must be exactly 2 sisters in the family.
The 2 sisters are:
Therefore, Sally has 1 sister.
Tests an AI's randomness and creativity
Here are 5 jokes:
How many are unique? 5 unique jokes.
Here are 5 jokes:
Why don't scientists trust atoms? Because they make up everything!
What do you call a bear with no teeth? A gummy bear!
Why did the scarecrow win an award? He was outstanding in his field!
What do you call a fake noodle? An impasta!
Why don't eggs tell jokes? They'd crack up!
All 5 jokes are unique - each one has a different setup and punchline, covering different topics (atoms/scie nce, bears, scarecrows, pasta, and eggs).
Tests an AI's ability to generate vector graphics
Tests an AI's ability to create detailed SVG illustrations of gaming hardware
Tests an AI's humor and creative writing ability
Recreate an interactive, nostalgic Pokémon battle UI in a single HTML file.
Tests an AI's ability to replicate an existing UI with Tailwind CSS
Tests an AI's ability to create interactive web elements
Tests an AI's ability to create a detailed world map in SVG format
Generate a single-page, self-contained HTML webapp using Tailwind CSS for a randomly chosen category/industry/niche.
Generate SVG art of a randomly chosen animal in a setting of its choosing.
Generate a unique and simple recipe with common ingredients.
8+ more head-to-head results. Free. Not a trick.
Free account. No card required. By continuing, you agree to Rival's Terms and Privacy Policy
