Claude 2.1 vs Kimi K2 (0905)
Anthropic Claude 2.1 | Moonshot AI Kimi K2 (0905) | |
|---|---|---|
| Overview | ||
| Company | Anthropic | Moonshot AI |
| Release date | Nov 21 2023 | Sep 5 2025 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 1T |
Context window | — | 256k |
| Benchmarks | ||
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. | — | 65.8% |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | — | 75.1% |
| Timeline | ||
| Release gap | Claude 2.1 shipped 654 days before Kimi K2 (0905) | |
Which is better: Claude 2.1 or Kimi K2 (0905)?
Claude 2.1 and Kimi K2 (0905) don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude 2.1 shipped 654 days before Kimi K2 (0905), so benchmark comparisons should account for the intervening progress.
Claude 2.1 is proprietary, while Kimi K2 (0905) is open weight.
Direct benchmark comparisons are unavailable — Claude 2.1 and Kimi K2 (0905) don't publish scores on any of the same benchmarks.
Frequently asked questions
Claude 2.1 was released by Anthropic on Nov 21 2023.
Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.
Claude 2.1 is a proprietary model released by Anthropic. Kimi K2 (0905) is an open weight model released by Moonshot AI.
Other comparisons
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