Glossary term

Open source

Software released under a license that allows others to use, study, modify and share it.

How it works

Open source software is released under a license that lets anyone use, study, modify and share it. For AI, a fully open release would include code, data and weights, though many 'open' models share only the weights under custom terms. Always read the license for limits on commercial use.

Open weights vs fully open source

Open weights

Weights downloadable
Data and code often withheld
Custom license

Fully open source

Code, data and weights
Permissive license
Reproducible

Why it matters

Open source drives much of AI tooling and research, and the term is debated when applied to models.

Related terms

Open weights Model hub Training data