GlobaLeaks is open-source software an organization runs to receive anonymous tips. It is associated with the Hermes Center in Italy. Sources can use Tor Browser. The setup supports more than one language, deletion deadlines, and a two-way conversation inside the system.
You do not “join GlobaLeaks” the way you join Signal. You use someone else’s instance, or you operate one. The operator can be a newsroom, a prosecutor’s office, or a project you have never heard of. Read who that is before you upload. A sloppy instance on a sloppy server is a trap with a logo. The code being open does not audit the server you are about to trust.
Use it to run a tip line, or to submit only where the operator is already known. globaleaks.org
If you operate GlobaLeaks, the server, the Tor setup, and the deletion deadlines are the security. A tip line that keeps everything forever is a database of sources. If you are the source, ask who runs it and what they promise to delete. Use Tor Browser. Do not attach a file whose name is your legal name. The software cannot fix a PDF that contains your letterhead.