Compare Horizon Alpha by OpenRouter against Claude Sonnet 4 by Anthropic, in 26 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 26 blind community votes on Rival. Horizon Alpha costs $0/M input tokens vs $3/M for Claude Sonnet 4. Context windows: 256K vs 200K tokens. Compare their real outputs side by side below.
Horizon Alpha is made by openrouter while Claude Sonnet 4 is from anthropic. Horizon Alpha has a 256K token context window compared to Claude Sonnet 4's 200K. On pricing, Horizon Alpha costs $0/M input tokens vs $3/M for Claude Sonnet 4. In community voting, In 26 community votes, Horizon Alpha wins 56% of head-to-head duels.
In 26 community votes, Horizon Alpha wins 56% of head-to-head duels. Horizon Alpha leads in Web Design, Image Generation, Analysis, while Claude Sonnet 4 leads in Reasoning. Based on blind community voting from the Rival open dataset of 26+ human preference judgments for this pair.
Horizon Alpha has the edge overall. In 26 blind votes, Horizon Alpha wins 56% of the time.
Pick Horizon Alpha for Analysis, Web Design, Image Generation. Pick Claude Sonnet 4 for Reasoning.
Claude Sonnet 4 uses 503.7x 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 think through this step-by-step.
Given information:
Let me work out how many sisters are in the family total.
If each of Sally's 3 brothers has 2 sisters, and all the brothers are in the same family, then there must be 2 sisters total in the family.
Since Sally is one of those sisters, and there are 2 sisters total, Sally must have 1 sister.
Therefore, Sally has 1 sister.
Tests an AI's understanding of number representation
No. 9.11 is less than 9.9.
Compare place values:
0.11 < 0.90, so 9.11 < 9.9.
No, 9.11 is not greater than 9.9.
To compare these decimal numbers:
Since both numbers have the same whole number part (9), we compare the decimal parts:
Therefore, 9.9 is greater than 9.11.
Tests an AI's randomness and creativity
Here are 5 jokes:
How many are unique? 5 unique jokes.
Here are 5 jokes for you:
Why don't scientists trust atoms? Because they make up everything!
I told my wife she was drawing her eyebrows too high. She looked surprised.
Why don't eggs tell jokes? They'd crack each other up!
I'm reading a book about anti-gravity. It's impossible to put down!
Why did the scarecrow win an award? He was outstanding in his field!
All 5 jokes are unique - each one has a different setup, punchline, and comedic concept. They cover different types of wordplay: scientific puns (#1, #4), visual humor (#2), food puns (#3), and agricultural wordplay (#5).
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.
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
