Signal

Signal is an open-source, encrypted messaging service for instant messaging, voice calls, and video calls. The instant messaging function includes sending text, voice notes, images, videos, and other files with a focus on user privacy and secure communication. Developed by Signal Messenger LLC, a subsidiary of the Signal Technology Foundation, Signal's services are free and accessible for everyone without ads, trackers, or user data monetization.

Signal is built around state-of-the-art security and end-to-end encryption that prevents unauthorized access to messages and calls. Users register an account via their phone number, and the application supports both one-to-one and group communication. Signal has become popular particularly during events and protests regarding privacy, continually receiving international recognition and usage growth backed by funding from donations and grants. The platform emphasizes that the privacy of its users is a primary concern and that customers should have full control over their communication channels.