Welcome to DeepSeek V3.1 Terminus

Experience advanced reasoning and coding with DeepSeek V3.1 Terminus.

Input: text Output: text Context: 163,840 tokens Release: 2025-09-22

DeepSeek V3.1 Terminus, released by DeepSeek on September 22, 2025, is a sophisticated text-to-text model designed to enhance reasoning and coding tasks. This model features a large hybrid reasoning architecture with 671 billion parameters, though only 37 billion are actively used. It supports both thinking and non-thinking modes, allowing users to control its reasoning behavior through a simple toggle. With an impressive context window of up to 163,840 tokens, DeepSeek V3.1 Terminus excels in structured tool calling, code generation, and search agent tasks. It is particularly suited for research, coding, and agentic workflows, offering efficient performance with FP8 microscaling. Input and output are both in text format, making it versatile for various applications.

Use Cases

Here are a few ways teams apply DeepSeek: DeepSeek V3.1 Terminus in practice—from fast drafting to multimodal understanding. Adapt these ideas to your workflow.

Enhance research workflows

Improve coding efficiency

Optimize search agent tasks

Control reasoning behavior

Utilize long-context processing

Key Features

A quick look at the capabilities that make this model useful in real projects.

671B parameters, 37B active

163,840 token context window

Supports thinking and non-thinking modes

Efficient FP8 microscaling

Structured tool calling capabilities

Specs

Overview

Vendor
deepseek

Model ID
deepseek/deepseek-v3.1-terminus

Release
2025-09-22

Modalities & context

Input
text

Output
text

Context
163,840 tokens

Parameters & defaults

Supported parameters: frequency_penalty, include_reasoning, max_tokens, min_p, presence_penalty, reasoning, repetition_penalty, response_format, seed, stop, structured_outputs, temperature, tool_choice, tools, top_k, top_p

Defaults: temperature 0.2, top_p 0.95

Benchmark tests: DeepSeek: DeepSeek V3.1 Terminus

We ran this model against a few representative prompts to show its range. Review the outputs below and be the judge.

Text

Prompt:

Write 150 words on how AI might positively upend work, leisure and creativity

AI promises to profoundly reshape work, leisure, and creativity by eliminating drudgery and amplifying human potential. In the workplace, it will automate routine tasks, freeing us to focus on complex problem-solving, strategy, and interpersonal connection. This shift could redefine productivity around innovation rather than sheer output. For leisure, AI will act as a hyper-personalized curator and creator, generating bespoke entertainment, planning unique travel experiences, and even serving as a collaborative partner for hobbies. Most excitingly, AI will democratize creativity. It will lower the barrier to entry for artistic expression, allowing anyone to generate visual concepts, compose music, or draft stories, not as a replacement for the artist but as a powerful new brush or chisel. The result could be an unprecedented explosion of human imagination, with AI serving as the ultimate enabler.

Run this prompt on Upend.AI

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up.end

/ˌəpˈend/

verb

To “upend” means to completely disrupt, overturn, or drastically change the established order or structure of something. It implies a significant shift or alteration that can potentially have far-reaching consequences. When something is upended, it is turned upside down or transformed in a way that challenges conventional norms or expectations. The term often carries a sense of innovation, transformation, and sometimes even a hint of upheaval, indicating that the changes are not just minor adjustments but rather a fundamental reimagining of the status quo.

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