Flash Sale: System Definition

Step 1: System Definition

It is seconds before noon. A limited-edition sneaker, or a steeply discounted phone, is about to go on sale. Thousands of shoppers already have the page open, finger over the buy button, waiting for the clock to hit zero.

A flash sale system is the part of an e-commerce site that runs sales like this one. A small stock of products is sold to a very large number of buyers in a short time. Traffic spikes the moment the sale opens. Hundreds of thousands of users can hit the site at the same time, and purchase requests far outnumber the items