Z.AI Co., Ltd., branded internationally as Z.ai, is a Chinese artificial intelligence company specializing in open weights large language models (LLMs). The company was formerly known as Zhipu AI outside China until its rebranding in 2025. Z.ai's flagship product is the GLM family of LLMs, which the company has released under the free and open-source MIT License since July 2025; they have also released vision language models and text-to-video models.