DeepSeek, a Hangzhou-based startup founded in 2023, shot to the top of Apple’s App Store free app chart after releasing a new open-source AI model it says rivals OpenAI's work. Its website was hit by outages amid a spike in interest.

DeepSeek is just one of an array of companies developing AI models and applications. Here’s a guide to a number of the biggest players in China.

Some AI researchers hailed DeepSeek’s R1 as a breakthrough on the same level as DeepMind’s AlphaZero, a 2017 model that became superhuman at the board games Chess and Go by purely playing against itself and improving, rather than observing any human games.