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Facebook Messenger is a free standalone chat application that is well integrated with the social network, Facebook. With Facebook Messenger you can stay in contact with friends and family, and other contacts from Facebook. The applicaiton has a ton of built-in features that make communication fun and engaging. Send images, gifs, video messages, voice notes, and stickers or share content from around the web. Facebook Messenger automatically syncs with your Facebook contacts without the need of adding phone numbers or identification manually.

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.

WeChat connects a billion people with voice calls, video calls, photo sharing, chats and payments. The multi-purpose application is developed by the Chinese company Tencent and is and in China, it is described as "the app for everything". WeChat is primarily developed for the mobile consumer, but is also avalible on desktop and in the browser.

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.

Slack is a new way to communicate with your team in a faster, better organized, and more secure than email. The software is designed for business looking to improve their communication work flow. Slack offers features like persistent chat rooms organized by topic, private groups, and direct messaging that is built for teamwork.

Zulip is an open-source real-time chat with an email threading model. With Zulip, you can catch up on important conversations while ignoring irrelevant ones. Zulip provides modern apps for every major platform, powered by Electron and React Native. The software is 100% open source software, built by a vibrant community of hundreds of developers from all around the world.