Hello George Onyango , thanks for reading the article. The tokens are generated by Firebase and sent to the client-side application, which could be web, iOS, Android, etc. The Firebase docs explain how to get the tokens: https://firebase.google.com/docs/cloud-messaging/js/client. This article covers only the server side (storing the tokens and making push notifications). I think the diagram here makes the flow a little clearer: https://tosinjs.hashnode.dev/build-a-push-notification-service-using-fcm-golang-and-mongodb#:~:text=A%20detailed%20flow%20diagram%20is%20shown%20below.