Open Source Kotlin Telephony Software

ARK-phone is a complete replacement for the Phone and Messages apps on Android, with free, end-to-end encrypted internet calls between friends. Share your ARK code, link a friend's code and call as usual: when the other phone is reachable the call goes over the internet free of charge, otherwise the same call goes through your carrier. No account, phone number or e-mail is needed. The audio is encrypted with WebRTC (DTLS-SRTP) and travels phone to phone; a relay is used only when no direct path exists and cannot decrypt anything. The dialer has a full in-call screen, a T9 keypad, recent calls with filters, contacts with favourites, dual SIM and flexible call blocking. As the default SMS app it handles SMS and MMS, including groups, with quick reply. No ads, no analytics and no tracking. Available in 11 languages. Source code, issues and discussions: https://github.com/jrs8205/ARK-phone

Fall in love with texting all over again with QKSMS! QKSMS is a beautiful, simple and customizable open source replacement to the stock messaging app on Android. It's got a clean, clutter-free intuitive design that lets you focus on what matters, plus millions of colors to choose from to make the theme of the entire app truly your own. QKSMS has some powerful features, including photo sharing, group chat, conversation blocking, message backup and restore and more. It's got everything you need from a text messaging app, plus all the fun features that make for a great text messaging experience. Simply put, QKSMS makes texting magical again, just the way it should be!