These days hardware and tech have come such a long way that building a service that supports millions of customers isn't hard at all. A colleague and I spent th

These days hardware and tech have come such a long way that building a service that supports millions of customers isn't hard at all. A colleague and I spent the last 3 years at work building a system that supports tens of millions of QPS, and we did 90% of the work ourselves. Of course this doesn't detract merit from the post. The devil is on the details, and there are many complexities other than raw scale.