Signal

Signal is recognized as one of the most secure messengers in terms of data exchange. Signal’s undisputed advantage is end-to-end encryption, which is provided by default, meaning only chat participants can read messages. The messenger ensures personal and group calls are protected. Initially, it was only available as a mobile app. Its desktop version came along when the need for a Chrome extension arose. In late 2017, Signal released a standalone app. Analysts say it is Signal that made end-to-end encryption widely used in messengers.

Threemа

Threema is a messaging service that uses end-to-end encryption (E2EE). It supports audio and video calls, file sharing, and other communication options. Threema was developed by Swiss company Threema GmbH. Experts name it as the messenger’s main advantage because of Switzerland’s better opportunities for Threema’s expansion. In 2020, developers added the option of a video call. Moreover, they claim that Threema is more secure than its popular analogs, including Telegram and Signal.

Wickr Mе

Wickr Me is another efficient instant messaging app. With Wickr Mе, users can exchange any messages, including audio, video, and text files. Like WhatsApp, it uses end-to-end encryption and is available for Windows, iOS, and Android. The app was launched in 2013 and quickly won users’ trust. Wickr Me developers say the messenger’s main difference from analogs is its absolute anonymity and reliability. Notably, Wickr Me does not leave traces on other devices and Internet servers.

Telegram

Telegram is the world's most popular cross-platform system for messaging and media files of any format. It uses closed source code, including under the GNU GPL license. In 2013, Telegram was developed by the Durov brothers, Pavel and Nikolai, who are also the founders of the VKontakte social network. The messenger attracts $13 million in funding annually. Notably, Telegram uses a unique MTProto protocol that facilitates high user protection. In 2022, the number of Telegram’s active users exceeded 700 million worldwide, and there is more to come.

Viber

Viber was developed in 2010 by Israeli experts Talmon Marco and Igor Magazinik. In March 2014, when the number of Viber’s active users reached 300 million, the app was acquired by Rakuten Group, a Japanese corporation. The use of end-to-end encryption makes Viber a highly secure messenger. In addition, it can add contacts without transferring data to the company's server. Viber’s distinguishing feature is the ability to partially encrypt metadata (these are user actions aimed at forming an individual digital fingerprint). Notably, there is no such function in WhatsApp and Telegram. Interestingly, communication via Viber is available for those without the app, and international calls are cheaper than with other messengers.