What is Shadow?
Shadow is a fully-open-source secure messenger for Android with end-to-end encryption and full administrative control. When whirlwinds of danger are raging around you, Shadow is your shade and shelter.
Why Shadow?
Shadow is strongly built upon Signal – the world leader of secure messaging. It goes further by placing the system server under your own control which is a must for a truly secure solution for corporations and teams. Like Signal, Shadow is 100% open source.
Why still Shadow, and not Signal?
Signal has been developing into a large centralized service with millions of subscribers. This has become cumbersome in terms of both functionality and system architecture to be applied to (relatively) small corporate deployments. We tailor the system towards specific needs of smaller teams.
For all that, why Shadow, and not messenger X?
That’s really a question of “messenger X” vs Signal.
Are you somehow affiliated with Signal?
We are not connected to Signal in any way. We are a team totally unrelated to Signal.
Is Shadow free of charge or paid?
The pre-built Shadow client is provided free of charge. The server has to be “activated” if the intended number of users is four or more. This is done by way of uploading an activation key to your Shadow server.
I would like to partake in (or invest into) your development!
Discussions are welcome.
What are server requirements?
Java 11, Redis, PostgreSQL and ScyllaDB. We recommend AlmaLinux 8, although Debian environments should be fine as well. Coturn is our choice for the NAT-T server. Minio is used for the private cloud functionality. Signal SFU is employed for group calls.
Can I use the Shadow source code?
For sure! – As long as you comply with the terms of open source licenses under which the system components are licensed. Here you go.