01
The short version
GLM-5.3 is open weight, but it is not released under the MIT license used by GLM-5.3-Flash. Z.ai uses a custom GLM-5.3 License for the flagship weights.
02
What the license permits
The license grants rights to use, copy, modify, merge, publish, distribute, sublicense and sell copies of the software, and explicitly includes running, deploying, fine-tuning and creating derivative works.
Its definition of the software includes model weights, parameters, configuration files, inference and training code, and associated documentation.
03
Can you use GLM-5.3 commercially?
Yes. The license grants commercial-use rights. The unusual condition is not a blanket restriction on commercial use; it applies to a narrower category of very large Model-as-a-Service businesses.
Most startups, agencies and ordinary end-user applications are not blocked merely because they make money with a product that uses GLM-5.3.
04
What counts as Model as a Service?
The license defines Model as a Service as giving a third party access to inference or fine-tuning in a way that gives that party meaningful control over inputs, parameters or training data.
It explicitly excludes end-user products where model capabilities are solely embedded in specific features or harnesses, and also excludes merely relaying requests to models hosted by others.
05
The US$10 billion condition
If the licensee or any affiliate operates a Model-as-a-Service business and their aggregate revenue exceeds US$10 billion over any consecutive 12-month period, Z.ai requires the business to pass its security review before using GLM-5.3 or derivative works for commercial purposes.
Both conditions matter: the business must fall within the license's Model-as-a-Service definition and cross the revenue threshold. The text refers to aggregate revenue of the licensee and affiliates, not only revenue generated by GLM-5.3.
06
What does the security review require?
The license says the scope and method of the security review are to be reasonably determined by Z.ai. The license itself does not publish a checklist of audits, certifications, fees or geographic conditions.
07
Fine-tuning, derivatives and redistribution
Fine-tuning and derivative works are explicitly permitted subject to the license conditions. If you distribute copies or substantial portions, the copyright and permission notice must be included.
The software is provided as-is without warranty, and use must comply with applicable laws and regulations.
08
Do not confuse GLM-5.3 with GLM-5.3-Flash licensing
The flagship GLM-5.3 repository labels its license glm-5.3. GLM-5.3-Flash has a separate MIT license. Models in the same family therefore should not be assumed to carry identical terms.
For deployment steps and hardware tradeoffs, see the GLM-5.3 local-running guide.
09
What teams should check before deployment
- Read the current official license file.
- Decide whether your product embeds the model as a feature or exposes model-level control.
- If you operate Model as a Service, evaluate the stated aggregate-revenue threshold.
- Preserve required copyright and permission notices when distributing copies or derivatives.
- Recheck the repository before a major commercial launch in case the license changes.
For most developers the license is not a blanket commercial-use barrier. For hyperscalers or complex enterprise structures, the exact definitions and threshold deserve formal legal review.
Sources
Primary and supporting sources
Facts were rechecked against the linked sources immediately before publication. Pricing, product availability and rollout status can change.