This is an online text chat system for budaev.info.

                                                                              xmpp.net score   

                                                                              Voice call pop-up:  Web-phone application popup

                                                                              Android clients: Conversations, Xabber, Yaxim
                                                                              iOS clients: ChatSecure, Monal
                                                                              Desktop clients: Gajim, Pidgin, Psi, Adium (OSX).
                                                                              Third-party web-based clients: Converse.js and Xabber Web.

                                                                              More information can be found on xmpp.org.