Technology

Z.ai reveals mystery AI model Ox Alpha is GLM-5.3-Flash

The Chinese tech firm stated that the model was tested anonymously on Chinese chips, navigating U.S. technology restrictions.

Updated Aug 28, 2026 · 08:28 UTC1 reports

The short version

Chinese tech company Z.ai revealed that the anonymous, popular AI model Ox Alpha was a test run of its new open-weight GLM-5.3-Flash model.
Z.ai claimed all test traffic for the multimodal model ran entirely on domestic Chinese AI chips through software and workload optimizations.
The Tsinghua University spinout, which went public in Hong Kong in January, previously ran a similar anonymous test for its GLM-5 model under the alias Pony Alpha.

Z.ai confirmed that the mystery AI model Ox Alpha, tested anonymously on OpenRouter and OpenCode, is its GLM-5.3-Flash model.[Business Insider]
Z.ai stated that all workload traffic for the Ox Alpha test was processed on Chinese AI chips despite U.S. technology export restrictions.[Business Insider]
GLM-5.3-Flash is a multimodal model that handles text, images, and video, with model weights made publicly available on Hugging Face.[Business Insider]
Z.ai went public on the Hong Kong Stock Exchange in January 2026 under Knowledge Atlas Technology at HK$116.20 per share before changing its English name to Z.ai in July.[Business Insider]
The company reported 724.3 million Chinese yuan in revenue last year alongside 3.2 billion yuan spent on research and development, resulting in a net loss of approximately 4.7 billion yuan.[Business Insider]

Independent verification of Z.ai's claim that Ox Alpha ran exclusively on domestic Chinese chips and hardware configurations was not provided.[Business Insider]