This application implements a secure and fully open source VoIP User Agent based on baresip library. Currently baresip app supports voice calls. text messages, voicemail Message Waiting Indication as well as blind and attended call transfers. Voice can be coded with Opus, AMR, G.729, G.722, G.722.1, G.726, or PCMU/PCMA codecs. Security is achieved via TLS or WSS SIP signaling transport and ZRTP or (DTLS) SRTP media encapsulation. Development of baresip app is motivated by need for a secure, open source SIP based VoIP User Agent for Android that does not depend on proprietary, third party push notification services. If you need video calling and have a device with Android version 7.0 or newer that supports Camera2 API at hardware Support Level LEVEL3, you can instead of this application install its sister application baresip+ from F-Droid. Source code is available at , where also issues can be reported.