# DeepSeek V3.1 Terminus

> DeepSeek V3.1 Terminus is an open-weight language model from DeepSeek, released on 22 Sept 2025. It accepts text and generates text, with a 164K-token context window and up to 147K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $0.27 per million input tokens and $1 per million output tokens (OpenRouter), across 1 provider we track.

Source page: https://www.aimodel.directory/models/deepseek-v3-1-terminus
Last verified: 4 Oct 2026

## Specifications

- **Developer:** DeepSeek
- **Release date:** 22 Sept 2025 (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Status:** Generally available
- **Weights:** Open weights (source: Hugging Face, https://huggingface.co/deepseek-ai/DeepSeek-V3.1-Terminus)
- **License:** mit (source: Hugging Face, https://huggingface.co/deepseek-ai/DeepSeek-V3.1-Terminus)
- **Parameters:** 685B (source: Hugging Face, https://huggingface.co/deepseek-ai/DeepSeek-V3.1-Terminus)
- **Context window:** 164K (163,840 tokens) (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Max output:** 147K tokens (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Knowledge cutoff:** 31 Mar 2025 (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Input:** Text (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Output:** Text (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Reasoning mode:** Yes (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Tool calling:** Yes (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Structured output:** Yes (source: OpenRouter, https://openrouter.ai/deepseek/deepseek-v3.1-terminus)
- **Hugging Face:** deepseek-ai/DeepSeek-V3.1-Terminus (source: Hugging Face, https://huggingface.co/deepseek-ai/DeepSeek-V3.1-Terminus)

## API pricing (USD per 1M tokens)

| Provider | Input | Output | Cached input | Context |
|---|---|---|---|---|
| OpenRouter | $0.27 | $1 | – | 164K |

## FAQ

### What is the context window of DeepSeek V3.1 Terminus?

DeepSeek V3.1 Terminus has a context window of 163,840 tokens (164K) and can generate up to 147,456 tokens in a single response, according to OpenRouter.

### How much does the DeepSeek V3.1 Terminus API cost?

DeepSeek V3.1 Terminus is listed from $0.27 per million input tokens and $1 per million output tokens (OpenRouter). Prices last verified 4 Oct 2026.

### Is DeepSeek V3.1 Terminus open source?

DeepSeek V3.1 Terminus is an open-weight model: its weights are published on Hugging Face as deepseek-ai/DeepSeek-V3.1-Terminus under the mit license. Check the license terms before commercial use.

### When was DeepSeek V3.1 Terminus released?

DeepSeek released DeepSeek V3.1 Terminus on 22 Sept 2025, according to OpenRouter.

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Data licensed CC BY 4.0. Cite as: AI Model Directory, "DeepSeek V3.1 Terminus", https://www.aimodel.directory/models/deepseek-v3-1-terminus