DeepSeek, a Chinese AI lab based in Hangzhou and spun out of the quantitative hedge fund High Flyer in 2023, has remained prominent since appearing on App Store charts in early 2025. Founded by Liang Wenfeng, the company offers AI chatbots and large language models, with flagship models including DeepSeek V4 (Flash and Pro), V3.2, and R1. Most models are open weights under the MIT license, plus a paid hosted API. The free web and mobile app is available on Apple App Store and Google platforms, with API pricing from roughly $0.14 per million input tokens and a context window of up to 1 million tokens on newer V4 releases. The company made global headlines in January 2025 when its R1 model reportedly matched top-tier reasoning performance at lower training costs. DeepSeek is known for low training and running costs, strong coding and math benchmarks, and visible chain of thought. Main criticisms include data stored in China, government bans, and political topic censorship. After testing the web app, mobile app, and Windows client over several weeks, the review team rated DeepSeek 2.1 out of 5.