Olvid is a messaging service from France which is useable without a phone number and accessible under Android and iOS (which allows running it on a tablet without a SIM-Card). It provides an end-to-end encryption which includes metadata and thereby can assure anonymity of its users.
European instant messaging apps
An instant messaging app allows people to send text messages and also media to each other. Many of them also support voice calls and video calls. There is a separate category for team communication services, which offer similar functions, but focuses on communication in a team, therefore also offers many additional features that would not be useful for private communication, like for instance integrations in project management software.
This category contains services from companies based in a member state of the European Union (EU), the European Economic Area (EEA) and the European Free Trade Association (EFTA).
You can read more about the listing criteria the listing criteria.
European services
Threema is an instant messaging app from Switzerland with Apps for iOS, Android, Windows, macOS and Linux. The communication is end-to-end encrypted and the apps are open source.
The app can be downloaded here:
TeleGuard is an instant messaging app from Switzerland with Apps for iOS, Android.
The App can be downloaded here:
ginlo Private is a instant messaging app from ginlo. ginlo is a company from Germany that also offers ginlo Business, a team communication service.
The app can be downloaded here:
SKRED is an end-to-end encrypted and peer-to-peer instant messaging service from France. They don't require a phone number or email address for usage and store minimal information (account token) about their users. Due to their peer-to-peer implementation, they can't store metadata about messages and don't restrict what files or messages you can send.