Doodle

Doodle is a platform that enables users to properly organize events, no matter if it’s a business meeting, a party, a BBQ, a book club, a play date, and so on. The most important aspect of the application is that the other users don’t need the have this app installed. They can also participate from the web version of the app.
The invitations to the meeting can be sent with WhatsApp, Facebook Messenger, Hangouts, eMail, and pretty much anything else. It also comes with calendar integration so that no conflicts will arise. In fact, people don’t even need an account with Doodle, and they just have to use the service.