Model access and licensing

Start by separating access from permission. Access tells you whether model files are available to you and whether you need to make a request. Permissions come from the terms that accompany the model. The Open Source Initiative’s definition describes the preferred form for modifying machine-learning systems as including data information, code, and parameters. It says the same requirements apply to a system, a model, weights and parameters, or other structural elements. Downloadable weights alone do not establish that a release meets those requirements. (Open Source AI Definition)

For a model you are considering, note whether weights are downloadable, whether access is gated, and which definition a publisher is invoking. Then follow the model’s license or terms link and check whether it covers your intended use.

• OSAID FAQs 5 min

  Read the OSI’s answers about its AI definition.

• Gated models 5 min

  Learn how a model author can enable access requests for model files.

Open weights

Model parameters available for download; permissions depend on the license.

Closed weights

Model parameters not distributed to users.

Open-source AI

An AI system that meets the OSI definition; downloadable weights alone do not show that it meets the definition.

Model license

Terms governing a model's use, modification, and distribution.

Open Weights Vs Open Source

A model’s license or other terms may set conditions on using or modifying it. The OSI definition says terms applied to model elements or their combinations may require a modified version to be released under the original terms. (Open Source AI Definition) Do not rely on a short license label alone to answer whether your intended use is allowed.

Open the terms for the specific model and check the activities that matter to your plan: commercial use, modification, attribution, and sharing copies or derivatives. Model-card metadata can display a license and link to a custom license. Follow any such link, and check for separate model-specific terms as well. Record which terms you reviewed so you can recheck them if the model page changes.

• The Open Source AI Definition 10 min

  Read the OSI’s description of conditions that terms may place on modified versions.

An access path affects what you can obtain and what steps you must complete. Hugging Face’s documentation describes gated models as models whose authors enable access requests. The author can configure automatic or manual approval, and can block access even after a request has been approved. (Gated models) Before requesting access, check what information you will share and what conditions the request asks you to accept.

For a model offered through a service, check the service’s terms alongside any model-specific terms. Using a model through an interface does not itself tell you whether its weights are downloadable or whether copies may be redistributed. Note whether your plan depends on file access, service access, or both, and check the relevant publisher pages.

• Model Cards 5 min

  See how model pages can display license metadata and link to a custom license.