Licensing

The code: MIT

Demucs itself is released under the MIT licence, which permits commercial use. It is developed at github.com/facebookresearch/demucs, and the repository notes that it is no longer actively maintained since its author left Meta. Demucs.net runs that code; it does not redistribute it or modify it.

The weights: unresolved

A model is code plus the weights it learned. The weights are the part worth being careful about.

The published Demucs weights were trained on MUSDB18-HQ. Most tracks in that dataset carry a Creative Commons Attribution-NonCommercial-ShareAlike licence, and its maintainers describe it as being for academic use. Whether a model's weights inherit the terms of the data they were trained on is an open legal question — courts have not settled it, and the Demucs project has published no commercial-use exemption.

So we will not tell you this is cleared, because it is not. What we can tell you is exactly what we run and on what basis, which is this page.

What we did about it

• We use the official weights and say so, rather than implying a clearance nobody has.
• The model layer is deliberately swappable. If this position has to change, moving to differently-trained weights is a configuration change here, not a rebuild — we are not locked in.
• We make no claim of affiliation with, or endorsement by, Meta Platforms, Inc. or the authors of Demucs.

None of this is legal advice, and none of it is a warranty. If your use is commercially significant, take your own advice rather than ours.

Your stems

Separately from all of the above: the recording you upload has its own copyright, and separating it does not change that. A stem pulled out of a track you do not own is still that track. You are responsible for holding the rights to whatever you upload and for what you do with what comes back.

Attribution

Demucs — © Meta Platforms, Inc. and affiliates, MIT licence. The full notice is in the project's LICENSE file.