DeepSeek V3.1 API

DeepSeek-V3.1 is the latest advanced LLM with improved architecture and performance across various natural language tasks.

Modalities: TextText
In / Out price: $0.2857/$1.06per 1M
Context window: 125K tokens
Released: Aug 28, 2025

DeepSeek V3.1 overview

DeepSeek V3.1 by DeepSeek

DeepSeek V3.1 is a large hybrid reasoning model supporting both thinking and non-thinking modes.

DeepSeek V3.1 specs

Model ID: deepseek/deepseek-reasoner-v3.1-terminus
Developer: DeepSeek
Context window: 128,000 tokens
Max output: 8,000 tokens
Input: Text
Output: Text
API: OpenAI-compatible, base URL https://api.aimlapi.com/v1

What Is DeepSeek V3.1 API?

DeepSeek-V3.1-Terminus is described as an update to DeepSeek-V3.1 that maintains the model’s original capabilities while addressing user-reported issues, including language consistency and agent performance.

It is presented as a large hybrid reasoning model that supports both thinking and non-thinking modes.

Technical Reference

Developer	DeepSeek AI
Model ID	deepseek/deepseek-reasoner-v3.1-terminus
Release Date	August 27, 2025
Context Window	128,000 tokens (~128K)
Max Output Tokens	8,000 tokens
Modalities	Text → Text
Capabilities	file input, streaming, structured (JSON schema) output, tool/function calling

What DeepSeek V3.1 Brings to the Table

Language consistency
The model is said to reduce CN/EN mix-ups and random characters in outputs.

Agent improvements
DeepSeek states that Code Agent and Search Agent performance were further optimized.

More stable outputs
The release notes describe the model as delivering more stable and reliable outputs across benchmarks than the previous version.

Hybrid reasoning
The model supports both thinking and non-thinking modes within a single architecture.

Where DeepSeek V3.1 Makes the Most Sense

Coding workflows
The model is positioned for coding-related tasks through improved Code Agent performance and better tool use.

Search and research tasks
The model is positioned for Search Agent workflows and structured tool calling.

Agentic workflows
The model is described as suitable for agentic workflows that benefit from stronger search and tool-use performance.

DeepSeek V3.1 vs the Alternatives

DeepSeek-V3.1
DeepSeek-V3.1-Terminus is described as an update to DeepSeek-V3.1 with improved language consistency and agent capabilities.

Sources: https://api-docs.deepseek.com/news/news250821/ · https://huggingface.co/deepseek-ai/DeepSeek-V3.1-Terminus · https://docs.cloud.google.com/gemini-enterprise-agent-platform/models/maas/deepseek/deepseek-v31

Use cases

DeepSeek V3.1 is documented as suited to advanced text generation. It is also documented for reasoning, coding, and tool use, including agentic workflows such as code agents and search agents.

It is documented as useful for code assistance. The model is also described as suited to coding and structured programming tasks.

It is documented as useful for search tasks and search-agent workflows. DeepSeek’s release note says it has stronger multi-step reasoning for complex search tasks, and the model is described as optimized for Search Agent performance.

It is documented as useful for enterprise RAG and conversational AI. One provider listing explicitly includes both as suitable uses for DeepSeek V3.1 Terminus.

Capabilities

File input
Streaming

DeepSeek V3.1 benchmarks by Artificial Analysis

See how DeepSeek V3.1 compares in generation speed and latency. Data retrieved Nov 3, 2026.

Speed#90 / 219121Output tokens / second Latency#173 / 2162.92Seconds to first token Humanity's Last Exam#171 / 45814.3%Score GPQA Diamond#152 / 43977.9%Score

Speed

Output tokens / second

Benchmark results

Compare 15 models available on AI/ML API across 5 independent benchmarks.

Humanity's Last Exam

Expert-written questions across academic subjects.

DeepSeek V3.1 API pricing

DeepSeek V3.1 pricing in US dollars
Usage	Price	Unit
Input	$0.2857	1M tokens
Output	$1.06	1M tokens
Cached input	$0.2857	1M tokens

Prices from the AI/ML API price list, checked on Nov 4, 2026.

DeepSeek V3.1 vs other models: token prices

AI/ML API input and output rates for 5 models, per million tokens.

AI/ML API model prices in USD per million tokens
Model	Input	Output
DeepSeek V3.1	$0.2857	$1.06
DeepSeek Chat (V4.1 Flash)	$0.3	$1.2
DeepSeek V4.1 Flash	$0.3	$1.2
DeepSeek V4 Flash Vision Exp	$0.44	$1.32
DeepSeek V4.1 Flash 1017	$0.39	$1.56

How to use the DeepSeek V3.1 API

View docs

Build with your agent

Give your agent the model details, code and documentation.

1Get your API key

Create API key

export AIMLAPI_KEY="8f2b4c7d9a1e6b3f…"

2Make your first request

curl 'https://api.aimlapi.com/v1/chat/completions' \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "deepseek/deepseek-reasoner-v3.1-terminus",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'

import os
import requests

headers = {
    "Authorization": f"Bearer {os.environ['AIMLAPI_KEY']}",
    "Content-Type": "application/json",
}
payload = {
    "model": "deepseek/deepseek-reasoner-v3.1-terminus",
    "messages": [
        {
            "role": "user",
            "content": "Write a haiku about the ocean."
        }
    ]
}

response = requests.post("https://api.aimlapi.com/v1/chat/completions", headers=headers, json=payload, timeout=120)
response.raise_for_status()
print(response.json())

const response = await fetch("https://api.aimlapi.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "deepseek/deepseek-reasoner-v3.1-terminus",
    "messages": [
      {
        "role": "user",
        "content": "Write a haiku about the ocean."
      }
    ]
  }),
});

if (!response.ok) throw new Error(`HTTP ${response.status}`);
console.log(await response.json());

DeepSeek V3.1 FAQ

What is the context window of DeepSeek V3.1?

DeepSeek V3.1 has a 128,000 tokens context window and can return up to 8,000 tokens.

What inputs and outputs does DeepSeek V3.1 support?

DeepSeek V3.1 takes text as input and returns text.

What is the model ID for DeepSeek V3.1?

Use deepseek/deepseek-reasoner-v3.1-terminus as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

When was DeepSeek V3.1 released?

DeepSeek V3.1 became available on August 28, 2025.

How much does DeepSeek V3.1 cost?

DeepSeek V3.1 costs $0.2857 input and $1.06 output per 1M tokens on AI/ML API, billed as you go with no subscription.

Does DeepSeek V3.1 support streaming?

Yes, DeepSeek V3.1 can stream responses as they are generated.

Who created DeepSeek V3.1?

DeepSeek V3.1 was built by DeepSeek.

Start building with DeepSeek V3.1

Get API key

DeepSeek V3.1 API

deepseek/deepseek-reasoner-v3.1-terminus

Build with your agent

Give your agent the model details, code and documentation.

1Get your API key

Create API key

export AIMLAPI_KEY="8f2b4c7d9a1e6b3f…"

2Make your first request

curl 'https://api.aimlapi.com/v1/chat/completions' \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "deepseek/deepseek-reasoner-v3.1-terminus",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'

import os
import requests

headers = {
    "Authorization": f"Bearer {os.environ['AIMLAPI_KEY']}",
    "Content-Type": "application/json",
}
payload = {
    "model": "deepseek/deepseek-reasoner-v3.1-terminus",
    "messages": [
        {
            "role": "user",
            "content": "Write a haiku about the ocean."
        }
    ]
}

response = requests.post("https://api.aimlapi.com/v1/chat/completions", headers=headers, json=payload, timeout=120)
response.raise_for_status()
print(response.json())

const response = await fetch("https://api.aimlapi.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "deepseek/deepseek-reasoner-v3.1-terminus",
    "messages": [
      {
        "role": "user",
        "content": "Write a haiku about the ocean."
      }
    ]
  }),
});

if (!response.ok) throw new Error(`HTTP ${response.status}`);
console.log(await response.json());

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DeepSeek V3.1 API

DeepSeek V3.1 overview

DeepSeek V3.1 by DeepSeek

DeepSeek V3.1 specs

What Is DeepSeek V3.1 API?

Technical Reference

What DeepSeek V3.1 Brings to the Table

Where DeepSeek V3.1 Makes the Most Sense

DeepSeek V3.1 vs the Alternatives

Use cases

Capabilities

DeepSeek V3.1 benchmarks by Artificial Analysis

Speed

Benchmark results

Humanity's Last Exam

GPQA Diamond

AA-LCR

IFBench

τ²-Bench Telecom

DeepSeek V3.1 API pricing

DeepSeek V3.1 vs other models: token prices

How to use the DeepSeek V3.1 API

Build with your agent

1Get your API key

2Make your first request

DeepSeek V3.1 FAQ

Start building with DeepSeek V3.1

DeepSeek V3.1 API

Build with your agent

1Get your API key

2Make your first request

DeepSeek V3.1 API

DeepSeek V3.1 overview

DeepSeek V3.1 by DeepSeek

DeepSeek V3.1 specs

What Is DeepSeek V3.1 API?

Technical Reference

What DeepSeek V3.1 Brings to the Table

Where DeepSeek V3.1 Makes the Most Sense

DeepSeek V3.1 vs the Alternatives

Use cases

Capabilities

Speed

Benchmark results

Humanity's Last Exam

GPQA Diamond

AA-LCR

IFBench

τ²-Bench Telecom

DeepSeek V3.1 API pricing

DeepSeek V3.1 vs other models: token prices

How to use the DeepSeek V3.1 API

Build with your agent

1Get your API key

2Make your first request

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Start building with DeepSeek V3.1