What is the difference between Claude Sonnet 4 and Horizon Alpha?

Claude Sonnet 4 is developed by Anthropic while Horizon Alpha is developed by OpenRouter. Claude Sonnet 4 has a 200K token context window vs Horizon Alpha's 256K. in 26 community votes on Rival, Horizon Alpha wins 56% of head-to-head matchups. These results are based on blind head-to-head voting across 34 challenges.

Which is better, Claude Sonnet 4 or Horizon Alpha?

Based on 26 community votes on Rival, Horizon Alpha wins 56% of head-to-head matchups against Claude Sonnet 4. Horizon Alpha is strongest in Web Design, Image Generation, Analysis. However, Claude Sonnet 4 leads in Reasoning.

How much does Claude Sonnet 4 cost compared to Horizon Alpha?

Claude Sonnet 4 costs $3/M input tokens and Horizon Alpha costs $0/M input tokens. Horizon Alpha is $3.00/M cheaper per input. Horizon Alpha also wins more often in community votes, making it the better value.

How are Claude Sonnet 4 vs Horizon Alpha votes collected on Rival?

Rival presents both models' outputs side-by-side in blind duels. Voters see the responses but don't know which model produced each one, eliminating brand bias. 26 votes have been collected for this pair across 34 challenges. All vote data is part of Rival's open dataset.

Updated Jul 2025

Claude Sonnet 4vsHorizon Alpha

Horizon Alpha wins 56% of 26 blind community votes against Claude Sonnet 4 on Rival.

Claude Sonnet 4 and Horizon Alpha compared across 34 shared prompts
Spec	Claude Sonnet 4	Horizon Alpha
Win rate	44%	56%
Input price	$3/M tokens	Free
Output price	$15/M tokens	Free
Context window	200K tokens	256K tokens
Weights	Closed	—
Free API (OpenRouter)	No	No
Released	May 2025	Jul 2025