You also can’t forget about the uber-popular WhatsApp. Like the others on this list, it promises end-to-end encryption so your messages stay private. The biggest advantage is that the service, which is owned by Facebook, has over a billion users. There’s a very good chance you won’t have to convince all your friends and family to download the app.

That shouldn’t be discounted, as one of the pains of moving to a messaging service is convincing everybody to jump aboard. However, WhatsApp is now owned by Facebook, a connection that could make some wary, especially since the social network recently announced it’d be using some account information, including phone numbers, from WhatsApp. If your goal is a high threshold of privacy, then it’s worth keeping an eye on.