I have developed a social platform where users can upload text posts, each time a user opens the app text posts pubished on the database are showed, we also have a page including posts under top hashtags, in app notifications, personal page with our posts showing and the ability to search for hashtags. I have to admit I didn't really take the download problem in consideration. I just tought that, since all the information is in string the download size would have been very low. Instead in the 5 days of the launch, with just 20 users our download size increased drastically reaching a value of 100MB a day. That's pretty high.
What are the best practicises to reduce download size in this situation? I woulf like to create a caching system: I want users to be able to see new posts without having to re-download all of them.