DeepSeek

What is DeepSeek?

DeepSeek is a family of open-source large language models developed by a Chinese AI lab that attracted global attention in early 2025 for matching the performance of top-tier proprietary models while costing a fraction as much to train and run. Because its weights are freely available for download and self-hosting, DeepSeek has become a favorite among researchers and developers who want capable AI without vendor lock-in or steep API fees.

How does DeepSeek work?

DeepSeek builds on a transformer architecture and uses a Mixture-of-Experts (MoE) design, which activates only a subset of the model's parameters for each request. This keeps inference efficient and inexpensive even at very large parameter counts.

Its reasoning-focused models are trained to "think" through problems step by step, producing a visible chain of thought before giving a final answer. You can use DeepSeek through its free web chat, via an affordable API, or by running the open weights on your own hardware or cloud.

Core features

• Open-source weights — models can be downloaded, fine-tuned, and self-hosted without licensing fees.
• Advanced reasoning — dedicated reasoning models work through complex math, logic, and coding tasks with a transparent thought process.
• Cost efficiency — Mixture-of-Experts architecture delivers strong results at a fraction of typical training and inference costs.
• Strong coding ability — performs well on programming benchmarks and everyday development tasks.
• Free access — a no-cost web chat plus low-priced API access lower the barrier to entry.

Pricing and alternatives

DeepSeek's web chat is free to use, and its API is priced well below most commercial competitors, making it attractive for high-volume workloads. Self-hosting the open weights can eliminate per-token costs entirely. Common alternatives include OpenAI's GPT models, Anthropic's Claude, Google's Gemini, and other open-weight families such as Llama and Mistral.

Who is it for?

DeepSeek is ideal for developers, researchers, and organizations that need strong language and reasoning performance on a tight budget, or that value the control and privacy of running models on their own infrastructure. If you want frontier-class capability without vendor lock-in or high API bills, DeepSeek is well worth considering.