The mystery behind Ox Alpha, a powerful AI model that quickly became one of the most popular models on OpenRouter, has been cleared up. Chinese AI company Z.AI, also known as Zhipu, has confirmed to Bloomberg that it created the model as part of its GLM family.
Ox Alpha appeared on OpenRouter over the weekend without revealing who developed it. The anonymous launch attracted developers because the model was available for free and delivered strong results in coding, reasoning and agent-based tasks. It also supports text, images and video.
The model gained users rapidly after its launch and soon reached the top of OpenRouter’s usage rankings, with usage reportedly more than double that of DeepSeek. Stripe CEO Patrick Collison, whose company is in the process of acquiring OpenRouter, also tested Ox Alpha and called it “very impressive.”
The launch was reportedly the biggest in OpenRouter’s history. Its unusually large free-access period added to the interest. OpenCode said developers could use the model throughout the week without the usual limits, while claiming that the underlying infrastructure could process up to 100 trillion tokens per day.
Even before Z.AI confirmed its involvement, developers and AI researchers had begun linking Ox Alpha to the Chinese company. Wccftech noted similarities in the model’s behaviour and tokenizer, while Z.AI’s earlier use of anonymous testing for another model further fuelled speculation.
Z.AI confirms Ox Alpha and plans to release its weights
Z.AI has now told Bloomberg that Ox Alpha belongs to its GLM series. The company also plans to release the model’s weights—the parameters that determine how an AI system processes information and produces responses.
Making the weights publicly available would allow developers to create their own applications and services using the model.
Z.AI is providing free access to Ox Alpha for one week, although the company has not yet announced its pricing once the free period ends.
The approach is not unique to Z.AI. Other Chinese technology companies, including Alibaba and Xiaomi, have also quietly introduced AI models without immediately revealing their identities. Such launches can give developers an opportunity to test a model and provide feedback before the company makes an official announcement.
Ox Alpha’s emergence comes as Chinese AI companies continue to produce increasingly capable models at comparatively low costs. Z.AI recently launched GLM-5.3, while companies including DeepSeek and Moonshot AI have also gained international attention for their AI offerings.
A useful next step would be to compare Ox Alpha, GLM-5.3 and DeepSeek on coding, reasoning, cost and open-weight availability.
