Term
DeepSeek V3.1
DeepSeek V3.1 is DeepSeeks open-weights hybrid model from August 2025 — it unifies a think and a non-think mode in a single model, with a 128K context and strong agentic skills.
DeepSeek V3.1 — explained in more detail
DeepSeek V3.1 was released on August 21, 2025 and is DeepSeeks first hybrid model: it unifies a fast non-think mode and a deeper-reasoning think mode in a single model, rather than shipping separate chat and reasoning models (V3 and R1) as before. The mode is selected via prompt template. DeepSeek positions V3.1 as an open-weights model whose weights live on Hugging Face; the code is MIT-licensed and the model license permits commercial use.
Key facts
- Release: August 21, 2025, access via open weights (Hugging Face) and the DeepSeek API.
- Architecture: Mixture-of-Experts with 671B parameters, roughly 37B active per token.
- Context window: up to 128,000 tokens (two-phase long-context training on top of V3).
- Hybrid inference: think and non-think mode in one model; per DeepSeek the think mode matches R1-0528 answer quality while responding faster.
- Efficiency: comparable benchmark scores at about 25 to 50 percent fewer tokens.
Example / Practical use
V3.1 suits operators who want to self-host a strong model or use it via API without proprietary lock-in. The open weights allow fine-tuning and on-premise deployment — relevant for data protection and cost control. The improved agentic skills and shipped example patterns (coding, Python-tool and search agents) make it attractive for agentic workflows.
Delimitation
V3.1 replaces the split setup of DeepSeek V3 (chat) and R1 (reasoning) with a single hybrid model. Unlike proprietary models such as GPT, Claude or Gemini, its weights are openly available, enabling self-hosting and adaptation — at the cost of higher infrastructure effort. Direct comparison models are other open weights as well as the mid-tier offerings of proprietary providers.