Thanks for reaching out to the Community about this.
Spotify constantly strives to improve the user experience with its features and the easiest way to achieve this is by regular app updates. That's why we appreciate you taking the time to share your suggestion about making folders public and providing an API for them.
We have an idea about making folders sharable here. Keep in mind that ideas with the status Closed - Not Enough Votes are still monitored by Spotify.
As a heads-up, it's good to know that the higher the number of votes an idea gets, the more likely it is for the idea to be implemented.