A Web app which helps to produce and gives better analytics about the best selling designs for your Merch account

This web app should be able to analyze trends on a site called Redbubble and use their Metadata to showcase the best selling print on demand designs on that platforms on specific dates,weeks,year and months.
When a user types a specific keyword it should list out the trending products of that specific keyword on redbubble and how much difficult would it be to rank for that keyword + what are the related keywords to that broad keyword and list out the low competition ones.