diff --git a/calsocial/models.py b/calsocial/models.py
index 2f3feba..bd274dd 100644
--- a/calsocial/models.py
+++ b/calsocial/models.py
@@ -35,6 +35,12 @@ users_roles = db.Table(
     db.Column('role_id', db.Integer(), db.ForeignKey('roles.id')))
 
 
+def generate_uuid():
+    from uuid import uuid4
+
+    return uuid4().hex
+
+
 class SettingsProxy:
     """Proxy object to get settings for a user
     """
@@ -197,6 +203,9 @@ class Event(db.Model):
     # pylint: disable=invalid-name
     id = db.Column(db.Integer(), primary_key=True)
 
+    #: The UUID of the event.  This is what is presented to the users and used in federation.
+    event_uuid = db.Column(db.String(length=40), unique=True, nullable=False, default=generate_uuid)
+
     #: The ID of the user who created the event
     user_id = db.Column(db.Integer(), db.ForeignKey('users.id'), nullable=False)