The messaging methods involve end-to-end encryption between the sender and the receiver.
The groups serve different purposes for different type of users. Hence it is easy for user access.
For a public group, the user can join at will. In case of private group, the user can request the admin for approval. Exclusive groups are secure groups where the admin has the access to invite the user.
You can invite/add any user to your group, if you are the admin of that respective group.
GapShup supports storing of data in text form, protected by a passcode.
The app lets you share last 10 messages of a group/individual chat to your email. Also, the media from the contacts/groups can be shared via email registered for backup purposes.