WhatsApp

They have different strengths, so it helps to decide first who you will talk to.

Threema describes itself as developed in Switzerland, with end-to-end encrypted messages, calls and files. Its site says it does not need a phone number or an email address, and that you use a Threema ID instead. It offers separate versions for private users, for companies and for organizations that want to run it on their own infrastructure.

Olvid says it asks for no phone number, email, name or surname, and that it never requests access to your address book. It states that everything is end-to-end encrypted, that it works without a SIM card, and that it runs on iPhone, iPad, Android, macOS and Windows. Its technology page says it has received security certification from the French agency ANSSI.

Wire presents itself as a secure messenger for organizations, with messaging, calls, conferencing and file sharing, all end-to-end encrypted and open source. Its about page says its headquarters are in Berlin. It is aimed at companies, governments and public bodies more than at family chats.

Whichever you choose, the app only helps if your contacts install it. Start with a small group, such as family or one team, and check that group chats, voice calls and file sharing work for them before you leave WhatsApp.