What is the difference between Claude Opus 4.8 and Grok 3?

Claude Opus 4.8 is developed by Anthropic while Grok 3 is developed by xAI. Claude Opus 4.8 has a 1.0M token context window vs Grok 3's 128K. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, Claude Opus 4.8 or Grok 3?

It depends on your use case. Claude Opus 4.8 and Grok 3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

How can I compare Claude Opus 4.8 and Grok 3 on Rival?

This page shows a side-by-side comparison of Claude Opus 4.8 and Grok 3 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 May 2026

Claude Opus 4.8vsGrok 3

Claude Opus 4.8 has a larger context window than Grok 3 (1.0M tokens vs 128K tokens).

Claude Opus 4.8 and Grok 3 compared across 52 shared prompts
Spec	Claude Opus 4.8	Grok 3
Input price	$5/M tokens	—
Output price	$25/M tokens	—
Context window	1.0M tokens	128K tokens
Weights	Closed	—
Free API (OpenRouter)	No	No
Released	May 2026	Feb 2025