Signal

Signal is fast, simple, secure messaging for the desktop. It now runs independently of your browser, so, if you’re a Firefox or Safari user, you don’t need to install Chrome to send and receive Signal messages on your computer anymore; if you’re a Chrome user, having your browser open will no longer be synonymous with having Signal Desktop open.

Features:

• Send high-quality group, text, voice, video, document, and picture messages anywhere in the world without SMS or MMS fees.
• Make crystal-clear voice and video calls to people who live across town, or across the ocean, with no long-distance charges.
• Signal messages and calls are always end-to-end encrypted and painstakingly engineered to keep your communication safe. We can't read your messages or see your calls, and no one else can either.
• Keep your chat history tidy with messages that you can set to disappear. Choose different disappearing message intervals for each conversation. Everyone in the thread shares the same setting. Good memories will last even if the words vanish.
• As an Open Source project supported by grants and donations, Signal can put users first. There are no ads, no affiliate marketers, no creepy tracking. Just open technology for a fast, simple, and secure messaging experience. The way it should be.