Claude Sonnet 4.5 vs DeepSeek V3.1 Terminus
Anthropic Claude Sonnet 4.5 | DeepSeek DeepSeek V3.1 Terminus | |
|---|---|---|
| Overview | ||
| Company | Anthropic | DeepSeek |
| Release date | Sep 29 2025 | Sep 22 2025 |
| Access | Proprietary | Open Weight |
| 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. | 79% | — |
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. | 77.2% | — |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | 50% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 83.4% | — |
Multimodal MMMUTests the AI on understanding images and text together across many college subjects. Higher is better. | 68% | — |
| Timeline | ||
| Release gap | DeepSeek V3.1 Terminus shipped 7 days before Claude Sonnet 4.5 | |
Which is better: Claude Sonnet 4.5 or DeepSeek V3.1 Terminus?
Claude Sonnet 4.5 and DeepSeek V3.1 Terminus don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. DeepSeek V3.1 Terminus shipped 7 days before Claude Sonnet 4.5, so benchmark comparisons should account for the intervening progress.
Claude Sonnet 4.5 is proprietary, while DeepSeek V3.1 Terminus is open weight.
Direct benchmark comparisons are unavailable — Claude Sonnet 4.5 and DeepSeek V3.1 Terminus don't publish scores on any of the same benchmarks.
Frequently asked questions
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
DeepSeek V3.1 Terminus was released by DeepSeek on Sep 22 2025.
Claude Sonnet 4.5 is a proprietary model released by Anthropic. DeepSeek V3.1 Terminus is an open weight model released by DeepSeek.