If you want to video chat with someone - but can't do so in real time because they have a busy work schedule or live in another time zone - Marco Polo is the app for you. This easy-to-use app combines the best of texting, social media and video chats on one platform. It's built into Google+, Gmail, YouTube and Google Voice, and the app is compatible on iOS, Android and online. It supports messaging and group chats, and has voice and video chat capabilities. Whereas Google Duo is meant to be much more specialized, Google Hangouts is ideal to use on desktops. Among its most unique features: Knock Knock, which gives users a preview of the person calling by firing up the camera on the other end of the line. It uses your phone number and accesses your phone's contacts list to let you start creating groups. You can use the Google Duo app on your Android phone, iOS smartphone, tablet or computer to video chat with up to eight of your friends at a time. Group FaceTime even allows you to chat with up to 32 people at once and can be used with almost all iOS devices with iOS 12 installed. While it's primarily for video chatting, you also can use it to make audio calls if you're in a spot that has a WiFi or data connection but a poor phone signal. Have an iPhone, iPad or Mac computer? You can use Apple's built-in FaceTime app to video chat with any of your contacts (as long as they also use the Apple platform).