Design a Ticket Sale Launch

Requirements

• •Show the list of shows with remaining availability
• •Hold a seat for one buyer for a limited time while they pay, and release it if they give up
• •Charge through an external payment provider and confirm the purchase
• •Notify the buyer by email, SMS and push after the purchase
• •Stop bots and abusive traffic without blocking real fans
• •Authenticate fans before they buy

Non-Functional Requirements

• •Opening rush: 50,000 fans on the site at 8:00 PM, each refreshing every 2 seconds; one page is about 10 requests (around 250,000 requests/second)
• •Up to 50,000 buy clicks in the same second when an extra show is announced
• •Zero double-selling: a seat is sold to at most one buyer
• •The external payment provider can take up to 30 seconds to answer; the site must stay responsive meanwhile
• •Losing a server, an availability zone or the primary database must not stop the sale
• •The team must learn about a problem before the customers do

Constraints

• •The payment provider is external and outside your control
• •A visual seat map is out of scope
• •One cloud provider, one region, at least two availability zones

Evaluation Criteria