Model weights are released under many different licences, and "open" rarely means "no conditions". Check the licence before building on a model.
Permissive Open-Source Licences
- Apache-2.0 and MIT allow use, modification and commercial distribution with few conditions, mainly keeping copyright and licence notices. Apache-2.0 also includes an explicit patent grant.
Responsible AI Licences
- OpenRAIL and similar licences permit broad use but add use restrictions — prohibiting certain harmful applications — which must be passed on to anyone you distribute the model to.
Custom Community Licences
Some widely used open-weight models ship with bespoke licences that may:
- require attribution in a specific form;
- restrict use above a certain number of users without a separate agreement;
- prohibit using outputs to train competing models;
- include an acceptable-use policy.
Non-Commercial Licences
Some models are released for research or non-commercial use only.
What to Check
- Is commercial use allowed?
- Are there user, revenue or deployment limits?
- Can you fine-tune and redistribute modified versions?
- Are there restrictions on using outputs?
- What attribution is required?
- What licences apply to the training data and any datasets you combine with it?
Keep Records
Record the model, version and licence used in each product, and review terms when upgrading. For significant commercial use, get legal advice — this guide isn't legal advice.