← Concept IndexDEFINITION WHY IT MATTERS COMMONLY CONFUSED WITH
Open vs. closed models
Also called: open weights, proprietary models, API-only
Closed models are used only through a provider's API, with the weights kept private. Open-weight models are downloadable and can be run and modified yourself, subject to their licence.
It shapes control, cost, privacy, and lock-in: an open-weight model can run inside your own boundary with your data never leaving; a closed one is easier to use but sends data to a provider and can change or disappear under you.
'Open' meaning free of all restrictions. Open weights still carry a licence that may limit commercial or other uses, and 'open' rarely means the training data is public.