Claude Sonnet 4.5 vs Horizon Alpha
Compare Claude Sonnet 4.5 by Anthropic against Horizon Alpha by OpenRouter, context windows of 200K vs 256K, tested across 26 shared challenges. Updated April 2026.
Which is better, Claude Sonnet 4.5 or Horizon Alpha?
Claude Sonnet 4.5 and Horizon Alpha are both competitive models. Claude Sonnet 4.5 costs $3/M input tokens vs $0/M for Horizon Alpha. Context windows: 200K vs 256K tokens. Compare their real outputs side by side below.
Key Differences Between Claude Sonnet 4.5 and Horizon Alpha
Claude Sonnet 4.5 is made by anthropic while Horizon Alpha is from openrouter. Claude Sonnet 4.5 has a 200K token context window compared to Horizon Alpha's 256K. On pricing, Claude Sonnet 4.5 costs $3/M input tokens vs $0/M for Horizon Alpha.
No community votes yet. On paper, Claude Sonnet 4.5 has the edge — newer, major provider backing.
Style Comparison
Claude Sonnet 4.5 uses 490.1x more bold
vs
Ask them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
