CircularMonster sells used items like laptops, mouse, keyboards etc. They used to manually create batches on excel, email the details to different potential buyers who would bid an amount on that batch. Then maintain the bids on a separate excel sheet. The web app / portal we developed automates this complete process. It gives the ability to the admin to login to his dashboard, upload batches and manage batches and be able to invite potential buyers and send email notifications, all from within the portal. Potential buyers generally prefer bidding over emails. Circularmonster allows them to bid quickly by replying to the email notification they received, without going through the hassles of signing into the portal as well as they can login to view and manage their bids. In order to integrate bid from email replies back into the portal, we used postmark web hooks, explained in detail in our blog post about how to integrate postmark with bubble.io apps