Skype is a VoIP and IM client. The service allows users to communicate with peers by voice using a microphone, video by using a webcam, and instant messaging over the Internet.
Hangouts bring conversations to life with photos, emoji, and even group video calls for free. Connect with friends or Teams across computers, Android, and Apple devices.
Open source, private cloud Slack-alternative team chat platform. Workplace messaging for web, PCs and phones. MIT-licensed. Secure, configurable, and scalable from teams to enterprise.