DeepSeek V3.1 API

DeepSeek-V3.1 is the latest advanced LLM with improved architecture and performance across various natural language tasks.
Context
128K tokens
Input
$0.351 / 1M
Output
$1.3 / 1M
Released
Aug 28, 2025

How to use DeepSeek V3.1 API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to deepseek/deepseek-reasoner-v3.1-terminus.
import requests

r = requests.post(
    "https://api.aimlapi.com/v1/chat/completions",
    headers={"Authorization": "Bearer " + AIMLAPI_KEY},
    json={
      "model": "deepseek/deepseek-reasoner-v3.1-terminus",
      "messages": [
        {
          "role": "user",
          "content": "Hello!"
        }
      ]
    },
)
print(r.json())
const r = 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": "Hello!"
      }
    ]
  }),
});
console.log(await r.json());
curl -X POST 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":"Hello!"}]}'

OpenAI-compatible — swap the base URL and it works with your existing SDK.

DeepSeek V3.1 API Pricing

TypePrice
Input
$0.351 / 1M
Output
$1.3 / 1M
Cached input
$0.351 / 1M

DeepSeek V3.1 Terminus has a documented pricing caveat: DeepSeek says its API uses cache-hit/cache-miss and peak/off-peak pricing, with off-peak rates half of peak rates, and its V3.1 release note says new pricing

DeepSeek V3.1 vs other models

ModelInputOutputContextBest for
DeepSeek V3.1
This page
$0.351 / 1M
$1.3 / 1M
128K tokens
Agentic workflows and structured output
$1.625 / 1M
$1.625 / 1M
128K tokens
Reasoning + agents
$0.34385 / 1M
$1.03155 / 1M
128K tokens
Reasoning + agents
$0.039 / 1M
$0.156 / 1M
128K tokens
Reasoning + agents

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