Claude Sonnet 4 vs Grok 4 Fast
Anthropic Claude Sonnet 4 | SpaceXAI Grok 4 Fast | |
|---|---|---|
| Overview | ||
| Company | Anthropic | SpaceXAI |
| Release date | May 22 2025 | Sep 2025 |
| Access | Proprietary | Proprietary |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 30% | — |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 72.7% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 75.4% | — |
| Timeline | ||
| Release gap | Claude Sonnet 4 shipped 102 days before Grok 4 Fast | |
Which is better: Claude Sonnet 4 or Grok 4 Fast?
Claude Sonnet 4 and Grok 4 Fast don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude Sonnet 4 shipped 102 days before Grok 4 Fast, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — Claude Sonnet 4 and Grok 4 Fast don't publish scores on any of the same benchmarks.
Frequently asked questions
Claude Sonnet 4 was released by Anthropic on May 22 2025.
Grok 4 Fast was released by SpaceXAI on Sep 2025.
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