does the person on the other side need the app as well in order to receive the calls?

Open Whisper Systems is killing it. RedPhone, TextSecure and now Signal.

This needs more upvotes

Awesome App!! Perfect for personal chat at work while under work company's wifi network.

Great app for iPhone. I'm looking forward to video calls in the desktop app

Are you planning to add video calls to the desktop app?

Signal is the alternative to personal conversations being monetized and the possibility of compromised personal information.

Pros:

Cross-platform, end-to-end encryption, text and voice messages plus voice and video calls 💯

Cons:

While these features are now available in Signal, it lagged in bringing emoji skintone support, among others.

Today people not often share highly confidential data in messages, but end-to-end encryption serves as an extra safety measure when you are sending any private information like payment details, Social Security numbers, usernames, passwords, etc. The Signal messenger app is a great example of how to make communication secure.

The only good alternative to Whatsapp IMO. Once Whatsapp was purchased by Facebook, they had a very short time period where you can opt out of having your conversations recorded and sent to Facebook. If Facebook has your data, so does everyone else. I've been using it for several years now and it's always been reliable and easy enough to use that I can bring new people into the app. I like it the way it is.

Interesting program. By the way I find something similar at Computools.They develop very useful apps