I need to create a Restful API backend for my flutter app using NodeJS with Mysql. I'd like to restrict endpoint access to just the Flutter client. The user shouldn't have to register and the only requirement is that the API is accessed through the Flutter app. I thought I might be able to make use of an FCM token which is generated as soon as the app is fired up. But I'm guessing this would require some kind of anonymous registration of the token to the database.
I wonder if there's a simpler way that I'm overlooking?