I am creating an app where people can create items and put them into collections.

To give it a ‘single page app’-like feel, I want people to be able to click on an ‘edit’ icon and edit and update one of the items in-place.

Now there is a choice here to use AJAX to do the updating behind-the-scenes, or to use Phoenix Channels.
One advantage that channels might have, is that a user could listen to each item’s topic, and also be notified when another user makes a change in one of the items.

However, the application will contain hundreds of items per collection, meaning that users might subscribe to many, many topics while they browse through a collection. Would this pose a problem?

Also, I wonder what the best way would be to serialize a form while using Phoenix Channels.

What is the better option here?