How to Use DeepSeek API — Complete Guide 2026

Published September 15, 2026 · Estimated reading: 7 min

DeepSeek offers some of the most cost-effective LLM APIs available today. This guide covers everything you need to get started — from your first API call to production deployment, including pricing, streaming, tool calling, and how to access DeepSeek models through alternative routes.

What is DeepSeek API?

DeepSeek API provides access to DeepSeek's family of language models, including DeepSeek-V4-Flash (fast, affordable) and DeepSeek-V4-Pro (stronger reasoning). Both models support:

OpenAI-compatible chat completions endpoint
Streaming (SSE) responses
Tool calling / function calling
Prefix caching (automatic, reduces cost significantly)
Vision (image understanding on Pro)

Method 1: Direct DeepSeek API

curl https://api.deepseek.com/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-your-deepseek-key" \
  -d '{
    "model": "deepseek-chat",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

DeepSeek Official Pricing (2026)

Model	Input (cache hit)	Input (cache miss)	Output
DeepSeek Flash (off-peak)	$0.05/M	$1.58/M	$4.75/M
DeepSeek Flash (peak)	$0.10/M	$3.17/M	$9.50/M
DeepSeek Pro (off-peak)	$0.25/M	$1.58/M	$4.75/M
DeepSeek Pro (peak)	$0.50/M	$3.17/M	$9.50/M

Note: Peak hours are 9:00-23:00 Beijing time (UTC+8). Cache hits apply to repeated prefix tokens.

Method 2: DeepSeek via AI24X Gateway

If you prefer a single API key for multiple models, automatic fallback, and unified billing, you can access DeepSeek models through the AI24X Gateway. No DeepSeek account needed — just one AI24X key.

curl -X POST "https://api.ai24x.com/v1/chat/completions" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-your-ai24x-key" \
  -d '{
    "model": "vip-ds-flash",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

Python SDK Example

from openai import OpenAI

client = OpenAI(
    base_url="https://api.ai24x.com/v1",
    api_key="sk-your-key"
)

# DeepSeek Flash
response = client.chat.completions.create(
    model="vip-ds-flash",
    messages=[{"role": "user", "content": "Explain quantum computing in one sentence."}]
)
print(response.choices[0].message.content)

Node.js Example

const OpenAI = require("openai");
const client = new OpenAI({
  baseURL: "https://api.ai24x.com/v1",
  apiKey: "sk-your-key",
});
async function main() {
  const response = await client.chat.completions.create({
    model: "vip-ds-pro",
    messages: [{ role: "user", content: "Write a haiku about APIs." }],
  });
  console.log(response.choices[0].message.content);
}
main();

Streaming Example

Both DeepSeek direct and AI24X gateway support SSE streaming:

from openai import OpenAI

client = OpenAI(base_url="https://api.ai24x.com/v1", api_key="sk-your-key")
stream = client.chat.completions.create(
    model="vip-ds-flash",
    messages=[{"role": "user", "content": "Count to 10."}],
    stream=True
)
for chunk in stream:
    if chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)

Tool Calling Example

from openai import OpenAI

client = OpenAI(base_url="https://api.ai24x.com/v1", api_key="sk-your-key")

tools = [{
    "type": "function",
    "function": {
        "name": "get_weather",
        "description": "Get weather for a city",
        "parameters": {
            "type": "object",
            "properties": {
                "city": {"type": "string"},
                "unit": {"type": "string", "enum": ["celsius", "fahrenheit"]}
            },
            "required": ["city"]
        }
    }
}]

response = client.chat.completions.create(
    model="vip-ds-flash",
    messages=[{"role": "user", "content": "What is the weather in Tokyo?"}],
    tools=tools,
    tool_choice="auto"
)
print(response.choices[0].message.content)

Which approach should you choose?

	Direct DeepSeek	AI24X Gateway
Models	DeepSeek only	31+ (incl. DeepSeek, GPT-6, Claude, Gemini)
API Key	1 per provider	1 key for all
Fallback	Manual	Automatic
Billing	Per provider	Unified
BYOK	N/A	Bring your own DeepSeek key

Try DeepSeek through AI24X — one key, no account needed.

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