Claude Sonnet 4.5vsDeepSeek-V4-Flash-0731
Claude Sonnet 4.5 | DeepSeek-V4-Flash-0731 | |
|---|---|---|
| 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%Best | 38% |
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% | — |
Agentic terminal coding Terminal-Bench 2.1Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Higher is better. | — | 82.7% |
Personal tool use Toolathlon-VerifiedTests how well the AI uses everyday personal tools and apps to get things done — a human-checked version of Toolathlon. Higher is better. | — | 70.3% |
Cybersecurity CyberGymTests the AI on cybersecurity challenges — finding and exploiting software weaknesses inside a safe sandbox. Higher is better. | — | 76.7% |
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% | — |
Business workflows AutomationBenchTests whether the AI can run real multi-step business workflows — the kind of end-to-end office processes companies want to automate — from start to finish. Higher is better. | — | 25.1% |
Multimodal MMMUTests the AI on understanding images and text together across many college subjects. Higher is better. | 68% | — |
| Overview | ||
| Company | Anthropic | DeepSeek |
| Release date | Sep 29 2025 | Jul 31 2026 |
| Access | Proprietary | Proprietary |
Which is better: Claude Sonnet 4.5 or DeepSeek-V4-Flash-0731?
Claude Sonnet 4.5 leads DeepSeek-V4-Flash-0731 on 1 of the 1 benchmark they both report (BullshitBench v2). Claude Sonnet 4.5 shipped 305 days before DeepSeek-V4-Flash-0731, 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.
On BullshitBench v2, Claude Sonnet 4.5 leads at 79% vs DeepSeek-V4-Flash-0731 at 38%.
Frequently asked questions
Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.
DeepSeek-V4-Flash-0731 was released by DeepSeek on Jul 31 2026.
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