Telegram Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free. It is like SMS, but more powerful. . Free Open Source Mac Windows Linux Web Windows Mobile ... Android iPhone Blackberry Android Tablet BSD Windows Phone iPad Apple Watch Android Wear PortableApps.com FreeBSD Stickers Lightweight Built-in File transfer End-to-end encryption ... Cloud sync Encrypted chat Voice Call Ad-free Group chat Persistent History Public groups chat Share files Anonymous Secure Filesharing Built-in Photo editor Chat Bot Encrypted calls Encrypted VoIP calls GPS Location Tracking IFTTT integration In-Game Overlay Messages in cloud Multi Device Support Multiple Account support Works Offline Based on phone number Photo Sharing Portable Portable Linux Privacy protection Push to talk Search by tags Secret chats Security focused Self destructing messages Send Big files Share Videos Support for Themes Video calling Voice messages Add a feature 992 Like
Pidgin Pidgin is an easy to use, multi-protocol chat client client used by millions. Connect to AIM, MSN, Yahoo, XMPP, and more chat networks all at once. It has built-in... Free Open Source Mac OS X Windows Linux BSD PortableApps.com ... Xfce Multiple protocols Multiple protocols support Extensible by Plugins/Extensions Multiple languages ... Multiple Account support Multiple chat protocols Portable Supports XMPP Video calling Voice Call Add a feature 1431 Like
Adium Adium is a free and open source instant messaging application for Mac OS X, written using Mac OS Xs Cocoa API, released under the GNU GPL and developed by the Adium... Free Open Source Mac OS X Customizable Multiple languages Multiple protocols OTR ... Tabbed interface Support for Themes Add a feature 329 Like
Conversations Conversations is a privacy focused, open source XMPP Texting [Jabber] client for Android 4.0+ smart phones with wife-approved easy encryption [OTR, OMEMO, or GPG]. ... Free Open Source Android Android Tablet Decentralized End-to-end encryption Encrypted chat Picture sharing ... Group chat Self destructing messages OTR Add a feature 41 Like
Empathy Empathy is a messaging program which supports text, voice, video chat, and file transfers over many different protocols. You can tell it about your accounts on all those... Free Open Source Linux BSD Built-in File transfer Multiple protocols Video calling Add a feature 154 Like Discontinued Empathy is currently unmaintained. Last version, 3.25, released in August 2017, can be still downloaded from the official website.
Zulip Zulip is a group chat app. Its most distinctive characteristic is that messages are threaded by topic, helping you have long-running, organized conversations.... Free Open Source Mac OS X Windows Linux Web Android ... iPhone BSD Self-Hosted Threaded Conversations Group collaboration Chat Bot Community based ... GitHub integration Group chat Integrated File Sharing MarkDown support Team Collaboration Add a feature 109 Like
Miranda IM Miranda IM is the smaller, faster, easier instant messenger with support for multiple protocols. Designed from the ground-up to be resource efficient while still... Free Open Source Windows PortableApps.com Multiple protocols Portable Add a feature 222 Like
Psi Psi is an instant messaging application for Windows, Linux, and Mac OS X that connects to the free, open XMPP network. Localized versions of Psi are available in... Free Open Source Mac OS X Windows Linux BSD No features added Add a feature 77 Like
Xabber Open source Jabber (XMPP) client with multi-account support, clean and simple interface. Being both free (as in freedom!) and ad-free, Xabber is designed to be the best... Free Open Source Android Encrypted chat Add a feature 41 Like
Coccinella Coccinella is a free and open-source cross-platform instant messaging client with a built-in whiteboard for improved collaboration with other people. Free Open Source Mac OS X Windows Linux BSD No features added Add a feature 16 Like
Messenger for Desktop A simple & beautiful app for Facebook Messenger. Chat without distractions on any Operating System. Free Open Source Mac OS X Windows Linux No features added Add a feature 8 Like Bundleware Be careful during the installation: https://alternativeto.net/discussions/applications/11718/be-careful-in-the-installation/
MetroIRC An IRC client for the Windows desktop which follows the Metro design guidelines. Free Open Source Windows No features added Add a feature 7 Like
qutIM qutIM - free open-source multiprotocol ( ICQ, Jabber/GTalk/Ya.Online/LiveJournal.com, Mail.Ru, IRC ) instant messenger for Windows, Linux, MacOS X, OS/2, Symbian... Free Open Source Mac OS X Windows Linux S60 BSD ... Haiku Multiple protocols Add a feature 27 Like Discontinued The project seems to be no longer developed. Last versions for Windows, Mac, Linux and other platforms can be still downloaded from the official website.
Zom Zom's security and privacy features are powered by the amazing foundation created by the ChatSecure project, and works with other great apps like Conversations. Free Open Source Android iPhone Encrypted chat OTR Picture sharing Voice messages Add a feature 3 Like
Tinode Open source instant messaging server and clients. Backend in pure Go (license GPL 3.0), client-side binding in Java for Android and Javascript (license Apache 2.0)... Free Open Source Web Android Self-Hosted Ad-free Group chat Real time collaboration Add a feature 2 Like