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Claude Sonnet 4 vs DeepSeek V3.1 Terminus

2 vs 0 benchmarks won

Anthropic
Claude Sonnet 4
DeepSeek
DeepSeek V3.1 Terminus
Overview
CompanyAnthropicDeepSeek
Release dateMay 22 2025Sep 22 2025
Model type
Open sourceNoYes
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
75.4%
Software engineering
SWE-Bench Verified
72.7%
Multimodal understanding
MMMU
Timeline
Release gapClaude Sonnet 4 shipped 123 days before DeepSeek V3.1 Terminus

Which is better: Claude Sonnet 4 or DeepSeek V3.1 Terminus?

Claude Sonnet 4 leads DeepSeek V3.1 Terminus on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude Sonnet 4 shipped 123 days before DeepSeek V3.1 Terminus, so benchmark comparisons should account for the intervening progress.

DeepSeek V3.1 Terminus is an open-source / open-weight model; Claude Sonnet 4 is proprietary.

Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Claude Sonnet 4 released?
Claude Sonnet 4 was released by Anthropic on May 22 2025.
When was DeepSeek V3.1 Terminus released?
DeepSeek V3.1 Terminus was released by DeepSeek on Sep 22 2025.
Is Claude Sonnet 4 or DeepSeek V3.1 Terminus open source?
DeepSeek V3.1 Terminus is an open-source / open-weight model released by DeepSeek. Claude Sonnet 4 is a proprietary model released by Anthropic.

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