Syncthing is now MPLv2 licensed

We have changed the license the Syncthing is distributed under from GPLv3 to MPLv2. This license is a large blob of legalese but differs from the GPL essentially in that it allows you to combine syncthing with whatever larger work you may be building, and then distribute that larger work precisely as you see fit. You must however still provide source for Syncthing (including any modifications to the Syncthing source).

This opens up for distributing Syncthing and Syncthing-based works on the various app stores and including it in proprietary or otherwise licensed works.

Have fun.


Has everyone who contributed agreed to this change? If not, then their changes are still bound by the GPL, as they are the authors of their changes and own the rights to those specific changes.

Just a few links for you:

via email:

On So, 2015-03-08 at 15:52 +0100, Jakob Borg wrote: Hello dear contributor,

This is again one of those annoying bureaucratic moments where I propose a change of license and need everyone who is able and willing to accept the change. I promise this is absolutely the last time I’m doing a license change on this project…

I am proposing a change from the current GNU General Public License (v3) to the Mozilla Public License (v2). Please do read up on the differences if it interests you and you are unfamiliar with the details. I would summarize the relevant difference by saying that the MPLv2 is a more liberal copyleft license than GPLv3 - in practice somewhat of a step in between the MIT license and GPL. It still requires you to release any modifications you do as source (if you distribute your modifications), but it allows proprietary use of the code. This means we are able to release Syncthing on for example the Mac and iOS app stores, and it also means other people can incorporate Syncthing as part of their code with slightly fewer restrictions.

You have made contributions to Syncthing and must approve this change, or we cannot legally distribute your contribution under the new license.

There has been a short discussion about this on a forum thread ( Syncthing is going to be relicensed as MPLv2 - #19 by rumpelsepp) where it was decided there was no opposition to the MPLv2 license among the currently most active contributors. If you have a dissenting opinion, please do voice it in the discussion thread in question, but please still consider approving the change. :slight_smile: If, for whatever reason, this change is completely unacceptable to you then we need to know that as well, as a note on the pull request below.

To approve the change, leave a comment to that effect (something as simple as “I approve” or “:+1:” is good enough) on this pull request:

Relicense to MPLv2 by calmh · Pull Request #1421 · syncthing/syncthing · GitHub

Thank you!


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Or, to summarize, yes obviously all contributors have agreed to this.

This is good news, hopefully we’ll start to see more Syncthing clients on platforms like Windows Phone and iOS in the future.

And now since has literally no reason to continue on with Pulse, when are they going to be rebasing off new MPL Syncthing?

Feel free to sponsor us a Windows Phone;)

Note that the “split” (or non-merge as it were) with Indie didn’t have anything to do with the licensing, but views and ideas about the future. I always said that Indie probably needed less than syncthing for their pulse initiative rather than more. This has kind of been proven by there being no feature development at all on pulse from their side, although they have removed a few components that don’t make sense for them. So to be honest, I wouldn’t expect anything from there regardless of the license. But I am obviously not Indie and have no idea what they’re planning, so this is pure speculation. They are of course free to use and work with the MIT, GPL or MPL versions as they see fit – Syncthing offers a probably unprecedented choice in licensing at this point. :wink: