eBay's bulk upload functionality allows for a CSV import that can quickly generate a bunch of drafts or listings.

Whuppit should allow users to select cards from their inventory and generate a bulk upload file that users can then upload to eBay, making it much easier to quickly list a bunch of cards.

Biggest piece is probably talking to the grading company's API's to grab images for each card during that export functionality so that they can be used on the eBay listing without requiring any additional work for the users.