Well, although it seems doable in a reasonable time, there’re a few things you need to take care of from dev perspective e.g. http://stackoverflow.com/questions/22333237/generating-uniqu...
But from what we've gathered so far the most time-consuming thing for software developers (especially in e-commerce industry) is the maintenance phase. Meaning - the time when voucher campaigns are “in production”. Marketing team wants to stop the campaign as asap as possible, customer service team has to handle another customer coupon complaint, management wants to know the ROI of campaigns and so on. This is what our platform help solving too.