Share a graph
A Syncretic export (File › Export Project… in the app), made public, read-only, at a link. In the app, File › Share to the Web… does this in one step.
Drop a Syncretic export here
A .syncretic.json file, from File › Export Project… in the app
The first time you share under a username it becomes yours, and you get a key for it. Sharing under it again needs the key, so no one else can.
Updating a graph you made public before
Public graphs are listed under your username.