DeepSeek
: How to use it, features, and the business problems it solves
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What is DeepSeek?
DeepSeek is an open large language model (LLM) family, together with the AI chat and API services built on it, developed by DeepSeek (Hangzhou, China). You can try the latest flagship models, DeepSeek-V4 (V4-Flash / V4-Pro), for free in chat, while the developer API offers a 1M-token long context, Thinking mode, Agent capabilities, and OpenAI / Anthropic compatibility, all at a low price. DeepSeek also publishes purpose-built models such as the reasoning-focused R1 and its code and vision models.
Business problems it solves
About "DeepSeek"
What is DeepSeek
DeepSeek is an open large language model (LLM) family, together with the AI chat and API services built on top of it, developed by DeepSeek (Hangzhou, China). You can try its latest flagship models for free through its chat products (web and mobile app), while developers get high performance at a low price through its open API platform. By releasing high-performance models openly, DeepSeek has drawn attention worldwide.
Source: DeepSeek official site (the images below are from the same source)
Current models
DeepSeek publishes several models for different use cases. The current centerpiece is the fourth-generation DeepSeek-V4, with substantially strengthened Thinking mode and Agent capabilities.
01DeepSeek-V4 (V4-Flash / V4-Pro)
The latest flagship. It handles long contexts of up to 1M tokens and lets you toggle Thinking mode on or off. V4-Flash is fast and low-cost, while V4-Pro leans toward higher accuracy. Both support Tool Calls, JSON output, and OpenAI- / Anthropic-compatible APIs.
02DeepSeek R1 (reasoning-focused)
A model strong at "reasoning" — working through math, code, and logic step by step. It excels at tasks where the chain of thought leading to the answer matters.
03V3 / Coder V2 / VL / Math and more
A lineup of purpose-built models: the general-purpose V3, the Coder for code generation, VL (Vision-Language) that can also handle images, and the math-focused Math.
How to use
There are two ways to use DeepSeek: the free chat, and the developer API.
Try it in chat
Sign up for the web version (chat.deepseek.com) or the app, and chat with the flagship models for free.
Choose a mode
Switch between a standard response and Thinking mode depending on the task.
Integrate via API
Get a key on the open API platform and call the models in OpenAI or Anthropic format.
Because the API is OpenAI-compatible, migrating is easy — you can often just swap the endpoint in your existing OpenAI-targeted code.
Key features
01Thinking mode and Agent capabilities
V4 ships with Thinking mode as standard, solving complex problems step by step. V4-Flash greatly strengthens Agent capabilities, handling autonomous tasks that involve tool integration.
021M-token long context
Load large volumes of documents and code at once, and generate up to 384K tokens of output.
03Developer-friendly API
Supports both OpenAI and Anthropic formats. It offers Tool Calls, JSON output, the Responses API (V4-Flash), and Context Caching, with input pricing dropping sharply on a cache hit.
Pricing
Chat is free to use. The API is pay-as-you-go based on token volume, with per-million-token rates as follows (as of August 2026, in US dollars).
| Model | Input (cache miss) | Input (cache hit) | Output |
|---|---|---|---|
| deepseek-v4-flash | $0.14 | $0.0028 | $0.28 |
| deepseek-v4-pro | $0.435 | $0.003625 | $0.87 |
Pricing is based on the official rates as of August 2026. DeepSeek has announced an "across-the-board price increase (a significant hike)" coming soon, so always check the latest rates on the API pricing page. On a cache hit (reusing the same input), input pricing drops considerably.
How it differs from other LLMs
DeepSeek's strength is that it delivers high-performance models openly and at a low price. It offers a 1M-token long context and Thinking mode, yet its API rates are far cheaper than the major overseas proprietary models.
| Aspect | DeepSeek | Major overseas LLMs |
|---|---|---|
| Provider | DeepSeek (China) | OpenAI / Anthropic / Google and others |
| Price | Low (usage-based, with cache discounts) | Relatively higher |
| Openness | Models released openly | Mostly closed |
| Compatibility | Supports OpenAI / Anthropic formats | Each vendor's own, plus some compatibility |
For general-purpose chat, ChatGPT, Claude and Gemini are the competitors, while Qwen — another China-born, openness-oriented model — occupies a similar position. For developers who want to use high-performance models via API while keeping costs down, DeepSeek is a strong option.
FAQ
Q. Is DeepSeek free to use?
The web and app chat are free, and you can try the latest flagship models. Only API usage is pay-as-you-go.
Q. What is the current latest model?
It is the fourth-generation DeepSeek-V4. There is the fast V4-Flash and the higher-accuracy V4-Pro, both supporting a 1M-token long context and Thinking mode. The reasoning-focused R1 also remains available.
Q. How is my data handled?
The provider is a Chinese company (DeepSeek). Data handling follows its privacy policy and terms of service. If you work with sensitive information, review each provider's terms and its service region.
Q. Can I migrate from my existing OpenAI-targeted code?
Yes. The API supports the OpenAI format, so it is designed for easy migration — you simply swap the endpoint and API key.
The information on this page is based on what was published on the official site and the official API documentation as of August 2026. Models and pricing are subject to change, so please check the DeepSeek official site for the latest details.
