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DeepSeek-V3.1

DeepSeek

Released
August 21, 2025
Data date
September 8, 2026
Predecessor
DeepSeek-V3 0324
Price
Input · Output / 1M tokens
Input
Text
Output
Text

New in DeepSeek-V3.1 are separate thinking and non-thinking modes. The checkpoint remains a 671-billion-parameter mixture-of-experts model with 37 billion active parameters and a 128,000-token context window.

V3.1 follows DeepSeek-V3 0324 and is stabilized by DeepSeek-V3.1 Terminus. In the API, deepseek-chat and deepseek-reasoner represent separate usage modes even though they refer to one checkpoint.

Specifications and access

SpecificationValue and source
Weights
Open weightsSource
Access
API, LocalSource
Parameters
671BSource
Active parameters
Context window
128,000 tokensSource
License
Parameters
671 BSource
Active parameters
37 BSource
Architecture
MoE hybrid thinking/non-thinkingSource
Input
TextSource
Output
TextSource
Reasoning mode
thinking, non-thinkingSource
Tool calling
Training tokens
630B pre-training plus 209B continued training (Token counts describe extension/continued-training data, not a full pretraining corpus)Source