Really, their app is a mess, but from a delivery point of view their stuff is pretty good. Just yesterday I was going to redeem a deal and the store was closed

Really, their app is a mess, but from a delivery point of view their stuff is pretty good. Just yesterday I was going to redeem a deal and the store was closed to walk-ins, so I had to use the drive thru. I couldn't use the deal anymore because I had used the code already, and you can't apparently switch between walk in/drive thru mode. Luckily the drive-thru was so slow I was able to use the code (there's a timer on the code). That said, the backend worked great; I ordered on the mobile in-line and the order was in-store once I got to the drive thru order speaker. People forget how hard and expensive it was 10 years ago to do a realtime architecture. Today, McD gets information from your phone to wherever and down to the stores with maybe a few seconds of delay, so you can use your code at the in-store kiosk. And it has to integrate with their in-store order and payment systems. I'm disappointed at the article, because it doesn't talk about any of this stuff; it's just a laundry list of AWS services. That isn't the important stuff; the important stuff is really how they got all this legacy (in-store) and new stuff to work together.