AI Glossary / Core concepts
Open-source model.
Also known as: open-weight model, open weights, MIT licensed
An open-source model is one where the company releases the weights (the actual trained brain) for anyone to download and use. You grab it, often from a site called Hugging Face, run it on your own hardware, modify it, and even use it commercially. No restrictions.
That's the opposite of a closed model like Claude or GPT, where you only ever reach it through an API and never touch the model itself.
Why builders care: open weights mean Model-agnostic. If a model is good enough and free to run, you can build on it without paying per request or asking anyone's permission. The catch is you're now responsible for hosting it and keeping it running.