Signal has been designed for the mobile environment from the ground up. Messages and incoming calls are fully asynchronous; push notifications let you know when new messages have arrived, so they’ll be waiting for you if the app is in the background, your battery dies, or you temporarily lose service.
Make crystal-clear private phone calls to people who live across town, or across the ocean, with no long-distance charges.
All of our code is free, open source, and available on GitHub. This allows experts to verify our protocols and our cryptography.
Signal development is the result of hard work from Frederic Jacobs, Christine Corbett, and Tyler Reinhard, with big thanks for all the pull requests that came in from the community along the way.
Like everything we do at Open Whisper Systems, dedicated development is supported by community donations and grants. Signal contains no advertisements, and it doesn’t cost anything to use. Try it out!