Element is a secure collaboration and messaging app based on the Matrix protocol. It’s decentralised to deliver digital sovereignty, and based on an open standard for easy connections and interoperability. It is end-to-end encrypted by default.
Discord is a versatile communication platform that supports text, voice, and video interactions, offering organized servers for topic-focused discussions, customizable moderation tools, and low latency technology for smooth conversation and content sharing.
Slack is a unified communication platform built with an optimized workflow to keep modern teams focused and productive. A familiar chat interface facilitates discussions while advanced features are easily exposed based on context.
Mattermost is a secure, open source platform for communication, collaboration, and workflow orchestration across tools and teams.
TeamSpeak is a proprietary Voice over IP software that allows users to speak on a chat channel with other users, much like a telephone conference call. A TeamSpeak user will often wear a headset with an integrated microphone.
OpenTogetherTube lets you watch videos with your friends as easily as possible. It's completely open source, and able to be easily self-hosted via provided docker images.
Utopia P2P Ecosystem. Utopia is a feature-rich platform that is specifically designed to protect privacy of communication, confidentiality, and security of personal data. Utopia is a decentralized network, with no central server involved in data transmission or storage.
Video conversations with up to 8 people in your browser - no downloads, no login. Just name your channel and you are on. Works in all modern browsers, even mobile.
Dino is a modern open-source chat client for the desktop. It focuses on providing a clean and reliable Jabber/XMPP experience while having your privacy in mind. Using GTK+/Vala.
AirSend is a simple collaboration space for professionals and small teams that brings all your conversations, files, notes, and to-do lists into one place so that you can get work done faster and easier.
Live random video chat with opposite-gender partners On LuckyCrush, guys are connected to random girls and girls are connected to random guys!.
Dirc is a peer-to-peer web application which uses WebRTC to set up connections between chat participants without requiring a back-end server. The static files can be self-hosted. Other features:
Flingster is a chat service that focuses on local adults for flings, relationships, and dating.Warning
Not for children, because you do not know who is in the chat and IF THEY HAVE CLOTHES ON!
Self-hosted chat for small teams.
Let's Chat FeaturesDiscontinued
As stated at https://github.com/sdelements/lets-chat/issues/781 , the project is no longer developed since August 2017. Last version, 0.4.0, released in June 2015, can be still downloaded from GitHub together with the source code.