GLM-5.3-Flash
Description
GLM-5.3-Flash is an open language model from Z.ai, released on 2026-08-25. According to the model card, it is the first model of the GLM-5 series that understands images as well as text from the start. It has 320 billion parameters in total, of which 18 billion work on each step. The authors say it beats the previous GLM-5.2 across their tests and real tasks and comes close to Claude Opus 4.8 on programming and agent tests; these are the developer's own comparisons, not independent checks.
The model uses a new design that mixes two kinds of attention, which makes very long inputs cheaper to process. The model configuration allows a context of about one million tokens. The depth of reasoning can be set to low, high or maximum, and the card recommends passing a special setting for ordinary chat. The card lists English and Chinese. It works with SGLang, vLLM, Transformers, KTransformers and Unsloth.
The weights are public without any acceptance step. The license is MIT, which allows commercial use. We found no territorial restrictions in the license. The card does not state hardware requirements. The larger GLM-5.3 from the same developer is released under a separate GLM-5.3 license and is not covered by this card.
Date of check: 2026-10-21.
Pros and cons
Pros
- MIT license, weights open without an acceptance step
- Understands images as well as text
- Context of about one million tokens, cheaper long inputs
- Depth of reasoning: low, high or maximum
- Works with many tools: SGLang, vLLM, Transformers, Unsloth
Cons
- Large model: meant for servers, not home computers
- The card does not state hardware requirements
- Only English and Chinese are listed
- Video and audio input are not mentioned in the card
- Comparisons with other models come from the developer
Key facts
- License
- MIT
- Commercial use
- Allowed
- Developer
- Z.ai
- Interface languages
- English
- Checked on
- Oct 21, 2026