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Claude Sonnet 4 vs DeepSeek V3.1 Terminus

Anthropic Claude Sonnet 4 vs DeepSeek DeepSeek V3.1 Terminus — side-by-side specs.

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
Coding
SWE-Bench Verified
72.7%
Science
GPQA Diamond
75.4%
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 and DeepSeek V3.1 Terminus don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. 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 — Claude Sonnet 4 and DeepSeek V3.1 Terminus don't publish scores on any of the same benchmarks.

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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