DeepSeek Reasoner V3.1 API

DeepSeek Reasoner V3.1 excels in reasoning tasks with advanced chain-of-thought processing and the latest improvements in parameter activation.

Modalities
TextText
In / Out price
$0.529/$2.27per 1M
Context window
125K tokens
Released
Aug 28, 2025

DeepSeek Reasoner V3.1 overview

The pelican test: one prompt, every text model, unedited SVG output from Nov 3, 2026.

SVG of a pelican riding a bicycle, written by DeepSeek Reasoner V3.1 through AI/ML API

DeepSeek Reasoner V3.1 specs

Model ID
deepseek/deepseek-r1
Developer
DeepSeek
Context window
128,000 tokens
Max output
64,000 tokens
Input
Text
Output
Text
API
OpenAI-compatible, base URL https://api.aimlapi.com/v1

What is DeepSeek Reasoner V3.1 API?

DeepSeek Reasoner V3.1 excels in reasoning tasks with advanced chain-of-thought processing and the latest improvements in parameter activation.

Where to Use DeepSeek Reasoner V3.1

Coding and code review
Generate, debug, and review code across languages, reading whole files or repos in a single prompt.

Use cases

Software development: DeepSeek-R1 is documented as suitable for generating code snippets, debugging existing code, code reviews, and architecture planning.

Mathematics and scientific reasoning: It is documented as useful for complex math problem-solving, scientific reasoning, and other step-by-step reasoning tasks.

Content creation and summarization: It is documented as suited to generating written content, editing, and summarizing existing material, including long-document analysis and summarization.

Customer support and assistant workflows: It is documented as usable for customer service chatbots and for agent/workflow automation that requires multi-step planning and tool orchestration.

Capabilities

  • Streaming

DeepSeek Reasoner V3.1 benchmarks by Artificial Analysis

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

Speed

Output tokens / second

Benchmark results

Compare 7 models available on AI/ML API across 5 independent benchmarks.

Humanity's Last Exam

Expert-written questions across academic subjects.

DeepSeek Reasoner V3.1 API pricing

DeepSeek Reasoner V3.1 pricing in US dollars
UsagePriceUnit
Input$0.5291M tokens
Output$2.271M tokens
Cached input$0.5291M tokens

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

DeepSeek Reasoner 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
ModelInputOutput
DeepSeek Reasoner V3.1$0.529$2.27
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 Reasoner 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-r1",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'

Related articles

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DeepSeek Reasoner V3.1 FAQ

What is the context window of DeepSeek Reasoner V3.1?

DeepSeek Reasoner V3.1 has a 128,000 tokens context window and can return up to 64,000 tokens.

What inputs and outputs does DeepSeek Reasoner V3.1 support?

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

What is the model ID for DeepSeek Reasoner V3.1?

Use deepseek/deepseek-r1 as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

How much does DeepSeek Reasoner V3.1 cost?

DeepSeek Reasoner V3.1 costs $0.529 input and $2.27 output per 1M tokens on AI/ML API, billed as you go with no subscription.

Does DeepSeek Reasoner V3.1 support streaming?

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

Who created DeepSeek Reasoner V3.1?

DeepSeek Reasoner V3.1 was built by DeepSeek.

What kinds of tasks is DeepSeek Reasoner V3.1 best suited for?

It is designed for reasoning-heavy tasks that benefit from chain-of-thought processing before generating a response.

Start building with DeepSeek Reasoner V3.1

DeepSeek Reasoner V3.1 API

deepseek/deepseek-r1

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-r1",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'