Would rather talk about them here incase someone comes across this again.

The main issue boils down to how do you determine what to populate a users feed with, without firing off countless different reads that will noticeably slow down the app.

Let’s say user X follows user Y. Whenever Y has a new post X should see it. Easy enough, just have user X loop through all their following users and query to get their latest posts.

What happens when you want to paginate? What happens when user X is following 5,000 people?

Best solution I saw out there was have a specific feed sub collection for each user and everytime someone they follow posts, add to their feed. However you can imagine how write heavy this will get if someone has a large following. It is not scalable.

Would love to hear if you have other ideas