Slack

vs

WhatsApp

A VoIP application and platform designed for creating communities and connecting gamers, and people rallying around specific causes. The Discord client is a free to use and can handle text, image, video and audio communication between users in a chat channel. Currently over 250 million users use the software to connect with others across the globe.

Mattermost is an open-source, self-hostable enterprise team collaboration and messaging application. The software can be deployed to on-premis or to cloud instances. Mattermost is designed for internal use within organizations and businesses in financial services, government, healthcare, remote work, and enterprise DevOps, where teams use Mattermost to power collaboration at every stage of the DevOps lifecycle.

Microsoft Teams is your hub for teamwork, it brings together everything a team needs from chat and threaded conversations, meetings & video conferencing, calling, and content collaboration. With you can instantly go from group chat to video call with the touch of a button. Securely connect, access, share, and coauthor files in real time. While staying organized by keeping notes, documents, and your calendar together.

Signal is a cross-platform encrypted messaging application that has a strong focus on privacy. The application is developed by Signal Messenger LLC and provides users with features like one-to-one and group messages, which can include files, voice notes, images and videos. The software is famous for being used by the whistleblower and privacy advocate Edward Snowden who once said "I use Signal every day, it is the most scalable encryption tool we have".

With Telegram people can communicate and via instant messaging and voice over IP. Telegram is a cloud-based software and services that have a focus on privacy, speed and security. The client was initially created by the brothers Nikolai and Pavel Durov, the creators of the Russian social network VK back in 2013. Today the application is used cross-platform by over 400 million users world-wide.

Skype is a telecommunications application that specialize in providing video chat and voice calls between computers, tablets, mobile devices and consoles. The software allows you to connect with friends and business colleges worldwide. Skype provides free online calls, messaging, affordable international calling to mobiles or landlines and Skype for Business for effective collaboration among teams.