What is the difference between Claude Sonnet 4.5 and Sonoma Sky Alpha?

Claude Sonnet 4.5 is developed by Anthropic while Sonoma Sky Alpha is developed by OpenRouter. Claude Sonnet 4.5 has a 200K token context window vs Sonoma Sky Alpha's 2.0M. You can compare their actual outputs across 27 challenges on Rival to see how they differ in practice.

Which is better, Claude Sonnet 4.5 or Sonoma Sky Alpha?

It depends on your use case. Claude Sonnet 4.5 and Sonoma Sky Alpha each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 27 challenges so you can judge which fits your needs best.

How much does Claude Sonnet 4.5 cost compared to Sonoma Sky Alpha?

Claude Sonnet 4.5 costs $3/M input tokens and Sonoma Sky Alpha costs $0/M input tokens. Sonoma Sky Alpha is $3.00/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 Sonnet 4.5 and Sonoma Sky Alpha on Rival?

This page shows a side-by-side comparison of Claude Sonnet 4.5 and Sonoma Sky 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.

Updated Sep 2025

Claude Sonnet 4.5vsSonoma Sky Alpha

Sonoma Sky Alpha is cheaper than Claude Sonnet 4.5 at $0/M vs $3/M input tokens.

Claude Sonnet 4.5 and Sonoma Sky Alpha compared across 27 shared prompts
Spec	Claude Sonnet 4.5	Sonoma Sky Alpha
Input price	$3/M tokens	Free
Output price	$15/M tokens	Free
Context window	200K tokens	2.0M tokens
Weights	Closed	—
Free API (OpenRouter)	No	No
Released	Sep 2025	Sep 2025