What is the difference between Claude Opus 4.1 and Mercury 2?

Claude Opus 4.1 is developed by Anthropic while Mercury 2 is developed by Inception. Claude Opus 4.1 has a 200K token context window vs Mercury 2's 128K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.1 or Mercury 2?

It depends on your use case. Claude Opus 4.1 and Mercury 2 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does Claude Opus 4.1 cost compared to Mercury 2?

Claude Opus 4.1 costs $15/M input tokens and Mercury 2 costs $0.25/M input tokens. Mercury 2 is $14.75/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 Opus 4.1 and Mercury 2 on Rival?

This page shows a side-by-side comparison of Claude Opus 4.1 and Mercury 2 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 Mar 2026

Claude Opus 4.1vsMercury 2

Mercury 2 is cheaper than Claude Opus 4.1 at $0.25/M vs $15/M input tokens.

Claude Opus 4.1 and Mercury 2 compared across 53 shared prompts
Spec	Claude Opus 4.1	Mercury 2
Input price	$15/M tokens	$0.25/M tokens
Output price	$75/M tokens	$0.75/M tokens
Context window	200K tokens	128K tokens
Weights	Closed	—
Free API (OpenRouter)	No	No
Released	Aug 2025	Mar 2026