GLM-5.3-Flash is a native multimodal Mixture-of-Experts model from Z.ai, designed for efficient coding, long-horizon agentic tasks, and cybersecurity work. It is a lighter Flash variant of the GLM-5.3 family, built on the same post-training advances as GLM-5.3 with a hybrid sparse and linear attention architecture that maintains accurate long-context behavior. The model supports text, image, and video inputs and features built-in reasoning with configurable effort levels (low, high, max), making it well-suited for complex software engineering and autonomous agent workflows.