How to support sorting products by "Featured" and "Best Selling" attributes

[tiepbuijmvn]

Hi every one, 

We are developing a mobile integration app for our Shopify store.

As you guys can see that, in Shopify frontend --> customers can sort products by "Featured" and "Best selling" attributes.

We want to support this feature in our mobile app.
Can any one let me know which attribute or data from which API should we use to implement this?

Thank you.