DeepSeek is both the name of a Chinese AI company and the name of its chatbot and family of language models. The company became widely known when it built a model with quality close to the best US models at a much lower training cost and released its weights as open source. Its chatbot is free to use, and the open weights mean you can also run it yourself.

What is DeepSeek good for?#

  • Step-by-step problem solving: a math or physics student gives it a question and, in reasoning mode, sees the full solution step by step.
  • Programming: a developer gets PHP or Python code, has an error explained or a function rewritten; its quality in code is very good.
  • Everyday writing and translation: product descriptions, emails or translating an English paragraph at no cost.
  • Web search: with search turned on, it backs its answers with up-to-date internet sources.
  • A cheap API for a site: for a store chatbot or automatic categorization of reviews, a developer uses its API at low cost.
  • Local use: smaller versions of the model can be run on a personal computer or server so data doesn't leave the organization.

Strengths and weaknesses#

Strengths:

  • A completely free chatbot with quality close to paid models
  • Strong reasoning, math and coding
  • Open weights and a very cheap API

Weaknesses:

  • At busy hours it sometimes shows a "server busy" message
  • It doesn't have image generation or the multimodal features of competitors
  • Answers on politically sensitive topics are censored in line with the Chinese government's requirements
  • Online data is stored in China, so it isn't suitable for sensitive information

Free version and pricing#

DeepSeek's web chatbot and app are free and there is no subscription plan. The API for developers is billed by usage and is usually among the cheapest APIs for strong models. The model weights are released under an open license, and running them locally costs nothing beyond hardware. Check the official site for current API prices.

Language support#

DeepSeek understands many languages well and writes acceptable replies; it sometimes uses an unfamiliar word or a translation-like sentence, and sensitive text should be proofread. For technical work, asking in English and getting the reply in your language often gives more accurate results.

Getting started in three steps#

  1. Go to the official site and sign up with an email, or install the app.
  2. Turn on reasoning mode for logic problems and search for up-to-date topics.
  3. Never enter passwords, API keys or customer data in the chat.

DeepSeek alternatives#

  • ChatGPT: more of an all-rounder, with image generation.
  • Claude: more natural writing and more careful coding.
  • Qwen: another open-source Chinese competitor with a wider range of models in different sizes.
  • Kimi: a Chinese chatbot with strong search and long-document handling.

To understand open-source models better, read Open-source AI models: what they are and when they help; before work use, What never to give an AI: keys, passwords and customer data, and for API use, Estimating and reducing AI API costs will help.