# Z.ai Releases GLM-5.3-Flash, a 320-Billion-Parameter Open-Weight Multimodal Model Under an MIT License

The model ran anonymously on OpenRouter as "Ox Alpha" for a weekend and became the platform's most used model there before Z.ai confirmed the lineage.

- Published: 2026-08-27T06:20:08.967Z
- Canonical: https://polylog.news/ai/2026-08-27/z-ai-releases-glm-5-3-flash-a-320-billion-parameter-open-wei
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [Polylog editors](https://polylog.news), [MarkTechPost](https://www.marktechpost.com/2026/08/26/z-ai-releases-glm-5-3-flash-a-320b-a18b-natively-multimodal-moe-with-a-1m-token-context/)

Z.ai released GLM-5.3-Flash, a mixture-of-experts (MoE) model with 320 billion total parameters and 18 billion active per token, published with downloadable weights under an MIT license. It is the first natively multimodal model in the GLM-…

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