please let me know if this StackExchange isn't the place for this and I will move the question.
I'm trying to write a mobile app that will have a 'notification' aspect. I have web development experience so my references will include that :)
A "post" gets into my backend API/database for which there will be subscribers (app users), I want to notify those subscribers of the post, my app would then fetch the post and store it locally on the device. If this was a web application/service, I would use a Message Queue like RabbitMQ with consumers subscribing to an exchange, when a new event gets fired (e.g. "new-post:123") relevant consumers would get the message and fetch "https://domain.com/post/123" and do whatever they want with that. Although post 123 would still stay in the database on the API side, the consumer wouldn't need to fetch that post again. So consumer doesn't need to poll or list all posts to check if there is any new posts.. etc.
What is the approach taken in mobile development for such a need? I don't think I can rely on push notification services like OneSignal to take the place of message queues as push notifications don't seem to be reliable at all! Notifications get lost when mobile is offline for longer periods, or are delayed. Message queues on the other hand are very reliable; messages are persisted in exchanges/routes until they're consumed.