Your CONTRIBUTING.md file says "By contributing, you agree that your contributions will be licensed under its MIT License." Since OpenSign is AGPLv3, why don't you allow contributions under the same license, if the self hosted version will always be free? I'm worried that the purpose of that might be to let you make it proprietary later.

AGPL for thee but not for me, for I require MIT.

To be fair, this is an entirely reasonable way to do business, but it's also a bit funny.

I guess this allows them integrate with proprietary code on their back end if necessary, whilst making it hard for a competitor to take their code and undercut them, since most corps with proprietary software to protect won't touch AGPLv3 with a barge pole.

Nothing prevents an AGPLv3 fork if OpenSign goes proprietary in future.

I'd rather this approach than yet another non-standard Amazon-proof licence.

> I guess this allows them integrate with proprietary code on their back end if necessary

Couldn't they have accomplished that just by asking for GPLv3 instead of AGPLv3? That would let them do so without letting them make the self-hosted version non-free, unlike asking for MIT.

> Nothing prevents an AGPLv3 fork if OpenSign goes proprietary in future.

Yes, but this would be true for almost any FOSS license offered and regardless of what they ask of contributors.

> I'd rather this approach than yet another non-standard Amazon-proof licence.

I very much agree with this.