Open Weights

ELI5 - The Vibe Check

Open weights means you can download the actual trained numbers that make a model tick and run it yourself, on your own hardware, with your own rules. It's not the same as fully open source, though: the training data and code that produced those weights are usually still secret. Think of it as being handed the finished cake with no recipe, but you can still eat it, slice it, and remix the frosting.

Real Talk

Open weights refers to models whose trained parameters are publicly downloadable and runnable, as distinct from fully open source models where training data, training code, and evaluation harnesses are also released. Licenses vary widely, from permissive (Apache 2.0, MIT) to restrictive custom terms limiting commercial use or requiring attribution, so 'open weights' does not by itself guarantee unrestricted use.

When You'll Hear This

"Llama is open weights, not open source, the training data was never released." / "Check the license on those open weights before you ship them commercially."