Send Push Notification to Users Using Firebase Messaging Service in PHP

  To Day I am Explain about how to send Push notifications using Firebase Cloud Messaging (FCM) in web application FCM service is free of charge with some limitations. The size is limited to 2KB or 4KB depending on the type of data, and the message will be kept for default duration of 4 weeks before it gets deleted.
Browser Support:
Chrome: 50+
Firefox: 44+
Opera Mobile: 37+