How to Use DeepSeek: Web, Mobile App, and API Setup

Try DeepSeek in a browser

For most people, the fastest starting point is the official DeepSeek website. The Start Now route is the web experience, and the same homepage also points users toward API access and the mobile app.

That makes the browser version useful if you simply want to see the model’s response style before installing anything or writing code. If the web experience feels slow or unavailable, check the DeepSeek service status page; it posts incidents such as Web/APP performance issues and their resolution status.

Use the official mobile app

DeepSeek’s app announcement tells users to search for DeepSeek in their app store or visit the official website for direct links. The same notice warns users to download only from official channels to avoid being misled.

One important distinction: the app notice describes the app as 100% FREE - No ads, no in-app purchases, but API usage is a separate product area with its own Models & Pricing documentation. In other words, do not assume that a free app experience means your API usage will also be free.

Connect the API: the basic flow

For developers, the setup is straightforward. First, create a DeepSeek API key. Then include it in requests using the Authorization: Bearer <TOKEN> header format.

DeepSeek says its API format is compatible with OpenAI, so you can use the OpenAI SDK or software that supports the OpenAI API by changing the configuration, including the base_url. The core chat endpoint is /chat/completions, which creates a model response from the conversation history you send in a messages array.

Minimal HTTP request shape

Use this as a structure, not as a copy-and-paste production config. Put the official Quick Start base_url in <DEEPSEEK_BASE_URL>, and choose a current model ID from Models & Pricing or List Models.

POST <DEEPSEEK_BASE_URL>/chat/completions
Authorization: Bearer <DEEPSEEK_API_KEY>
Content-Type: application/json

{
  "model": "<MODEL_ID>",
  "messages": [
    {
      "role": "user",
      "content": "Explain DeepSeek in one short paragraph."
    }
  ]
}

DeepSeek’s Quick Start also notes that the v1 label used for OpenAI compatibility has no relationship to the model’s version, so do not read a URL path as a model-version signal.

First Python call with the OpenAI SDK style

DeepSeek’s own guides show examples that create an OpenAI(api_key=..., base_url=...) client and then call client.chat.completions.create. Keeping the API key, base URL, and model in environment variables makes it easier to change them later.

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ['DEEPSEEK_API_KEY'],
    base_url=os.environ['DEEPSEEK_BASE_URL'],
)

response = client.chat.completions.create(
    model=os.environ['DEEPSEEK_MODEL'],
    messages=[
        {
            'role': 'user',
            'content': 'Explain DeepSeek in one short paragraph.',
        }
    ],
)

print(response.choices.message.content)

Model names: do not rely on old examples

Before you copy a model name from a tutorial or older code sample, check the current DeepSeek docs. The Quick Start describes deepseek-chat and deepseek-reasoner in connection with DeepSeek-V3.2, while the Change Log says that during the current period those two names point to the non-thinking and thinking modes of deepseek-v4-flash, respectively.

That does not mean the docs are unusable; it means model aliases can change. For a new project or production deployment, confirm the exact model IDs in Models & Pricing and List Models before shipping.

Privacy, terms, and sensitive data

DeepSeek’s Privacy Policy says it applies to DeepSeek apps, websites, software, and related services. DeepSeek also publishes separate Terms of Use.

Before entering customer records, private source code, internal documents, or other sensitive material, review those documents alongside your own organisation’s data-handling rules. And for the mobile app, stick to the official download routes described in DeepSeek’s app notice.

Troubleshooting checklist

• Authentication error: Confirm that you created an API key and are sending it as Authorization: Bearer <TOKEN>.
• Unknown or invalid model: Recheck the current model name in Models & Pricing or List Models.
• Browser or app is slow: Look at the DeepSeek service status page for Web/APP incidents.
• Unsure which app to install: Use the app store search or official website links described by DeepSeek, and avoid unofficial download routes.
• Confused about cost: Treat the app’s free-use notice and the API pricing page as separate references.
• Confused by v1 in a URL: DeepSeek says the v1 used for OpenAI compatibility is not tied to the model version.

Bottom line

If you are exploring DeepSeek as a user, start with the official web experience or the official app. If you are a developer, create an API key, use Bearer authentication, and make an OpenAI-compatible /chat/completions request with a messages array.

Before you build on it seriously, check the current model list, pricing, privacy policy, and terms directly in DeepSeek’s official documentation.