Dialog Messenger Alternatives for Mac OS X

Skype is an instant messaging and VOIP (Voice Over Internet Protocol) client to communicate with people in a distant place.

Pidgin is a free and open-source chat client which supports AIM, Google Talk, ICQ, XMPP protocols.

WhatsApp Messenger is an instant messaging platform owned by Facebook.

Slack is a cloud-based team collaboration tool.

Mumble is an open source, low-latency, high quality voice chat software primarily intended for use while gaming.

Tox is a peer-to-peer instant-messaging and video-calling protocol that offers end-to-end encryption.

Viber Free Messenger and Phone Calls.

Discord is a freeware proprietary VoIP application designed for gaming communities.

Signal is the most scalable encryption tool.

Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application.

Glip is fully searchable, real-time group chat; video chat, task management, file sharing app.

TeamSpeak is software for quality voice communication via the Internet.

LINE is a new communication app which allows you to make free voice calls and send free messages whenever and wherever you are.

RetroShare is open source software for encrypted filesharing, serverless email, instant messaging, online chat, and BBS, based on a friend-to-friend network built on GNU Privacy Guard (GPG).

An alternative to Dialog Messenger with similar functionality.

Mattermost is an open source, private cloud Slack-alternative, Workplace messaging for web, PCs and phones. MIT-licensed.

Wire is a cross-platform, encrypted instant messaging client created by Wire Swiss. It is available for iOS, Android, Linux, Windows, macOS and Web browser clients.

fluxday is a user-friendly, free & opensource task & productivity management tool for growing startups.

Franz is a free messaging app /former emperor of Austria, that combines chat & messaging services into one application.

Ring (SFLphone) is an open-source SIP-compatible softphone and instant messenger for Linux, Microsoft Windows, OS X and Android.

ICQ is an open source instant messaging software.

FaceTime is a proprietary videotelephony product developed by Apple Inc. FaceTime Audio is an audio-only version.

WeChat is a social media with instant messaging, commerce and payment services application.

Rocket.Chat free open source chat solution.

eXo Platform is an open source, standard-based, Enterprise Social Collaboration Platform.

Bitrix24 is a free (for small businesses) social enterprise platform.

Matrix is an open protocol for real-time communication. It is designed to allow users with accounts at one communications service provider to communicate with users of a different service provider via online chat, Voice over IP, and Videotelephony.

TribeScale is an All-in-One platform to coordinate your team around what really matters - communication, goals, decisions, tasks and results.

Curse is an online game portal and network of gaming websites.

Flock is a communication app for teams. Packed with tons of productivity features, Flock drives efficiency and boosts speed of execution.

Grape is an REST-like API framework for Ruby. It's designed to run on Rack or complement existing web application frameworks such as Rails and Sinatra by providing a simple DSL to easily develop RESTful APIs.

Fleep enables communication within and across organizations, be it your team chats, project communication or 1:1 conversations.

Zulip is a chat and collaborative software.

Gitter is an open source instant messaging and chat room system for developers and users of GitHub repositories.

Hubgets provides chat, voice and video turning team communication.