What DeepSeek Is and Who Builds It

DeepSeek is a family of AI models and a free chat assistant that became one of the most talked-about names in AI. It caught the world's attention for a simple reason: it delivered results that rival the big American labs while costing a fraction as much to build and to use. If you have heard people say "the AI that shook Silicon Valley," they were talking about DeepSeek.

This lesson gives you the foundation for everything that follows. You will learn who makes DeepSeek, how its models evolved, why it matters, and what makes it different from ChatGPT, Claude, and Gemini.

What You'll Learn

• Who builds DeepSeek and where the company is based
• The main model lines: V3, R1, and the newer V4 series
• Why DeepSeek's low cost and open weights are a big deal
• How DeepSeek is different from other AI assistants

Who Makes DeepSeek

DeepSeek is a Chinese AI company based in Hangzhou, China. It was founded on July 17, 2023 by Liang Wenfeng, who also serves as its CEO. The company grew out of High-Flyer, a Chinese quantitative hedge fund that Liang also leads. That background matters: High-Flyer had already built large clusters of AI chips for financial trading, which gave DeepSeek the computing power and engineering culture to train competitive models on a lean budget.

Unlike many labs that guard their models tightly, DeepSeek chose an unusually open path. It publishes technical papers describing how its models work and, for several of its models, releases the actual model weights under the permissive MIT license. That means anyone can download, study, modify, and run those models on their own hardware.

The Model Lineage

DeepSeek's models come in a few main lines. You do not need to memorize every version, but knowing the shape of the family helps you understand what you are using.

• DeepSeek-V3 is the general-purpose line, first released in December 2024. These are fast, capable "chat" models good at writing, summarizing, translation, and everyday questions. The line was updated through 2025 (V3.1 in August 2025, V3.2 in December 2025).
• DeepSeek-R1 is the reasoning line, launched publicly in January 2025 under the MIT license. R1 "thinks" step by step before answering, which makes it strong at math, logic, and multi-step problems. R1 drew huge attention for matching much more expensive reasoning models at a small fraction of the cost.
• DeepSeek-V4 is the newest line, previewed on April 24, 2026 with two variants: V4-Flash (fast and efficient) and V4-Pro (the higher-capability flagship). Both carry a large context window, meaning they can read a lot of text at once.

When you use the DeepSeek app, you usually do not pick a raw version number. Instead you toggle between a normal chat mode and a "DeepThink" reasoning mode, and DeepSeek maps those to the right underlying model. You will learn exactly how in a later lesson.

Why DeepSeek Matters

Three things make DeepSeek stand out from the crowd.

1. Cost. DeepSeek trained strong models for far less money than the headline figures reported by leading US labs, and it passes that efficiency on to users. Its chat app is free to use, and its developer API is among the cheapest ways to access a capable model. For students, small businesses, and anyone in a price-sensitive market, that changes what is affordable.

2. Open weights. Because several DeepSeek models are released under the MIT license, you are not locked in to one company's servers. Developers can download the weights, run them on their own machines or cloud, fine-tune them, and build products without paying per message. This "open-weight" approach is closer to Meta's Llama than to the closed models from OpenAI, Anthropic, or Google.

3. Strong reasoning. R1 proved that a smaller, cheaper lab could produce a top-tier reasoning model. That reset expectations across the industry and made high-quality step-by-step reasoning available to everyone.

How DeepSeek Differs From Other Assistants

If you already use ChatGPT, Claude, or Gemini, DeepSeek will feel familiar: you type a question, it answers. The differences are underneath.

• Openness: DeepSeek publishes weights for many models; the big US assistants generally do not.
• Price: DeepSeek is built around being cheap to run and use.
• Ecosystem: ChatGPT, Gemini, and Claude are tightly woven into large product ecosystems (Microsoft, Google Workspace, and a broad tool marketplace). DeepSeek is leaner and more focused on the raw model.
• Data location: DeepSeek is a Chinese company and stores user data on servers in China. This raises real privacy and compliance questions that you will study in the final lesson, and it is why some governments have restricted its use on official systems.

None of these makes DeepSeek automatically "better" or "worse." It makes DeepSeek a specific tool with clear strengths (cost, openness, reasoning) and clear trade-offs (data location, a smaller ecosystem). The goal of this course is to help you use those strengths on purpose and understand the trade-offs before you rely on it.

Key Takeaways

• DeepSeek is a Chinese AI company in Hangzhou, founded in 2023 by Liang Wenfeng and backed by the High-Flyer hedge fund.
• Its main model lines are V3 (general chat), R1 (step-by-step reasoning), and the newer V4 series (V4-Flash and V4-Pro).
• DeepSeek stands out for low cost, open-weight releases under the MIT license, and strong reasoning.
• It works like other AI assistants but differs in openness, price, ecosystem size, and where your data is stored.
• Understanding those trade-offs, especially data location, is part of using DeepSeek responsibly.