One of the most high load project we recently completed is Realtime Advertisement Bid Exchange. It was ordered by customer to optimise advertisers and publishers clients revenue in terms of advertising inventory sold. The key idea is to offer advertisement via auction to multiple potential advertisers and sell one who provides better bid.
Technically it means that all incoming ad traffic should be multiplied by number of auction participants. For example for 10k auctions per second and 10 participants, there should be processed 100k http requests per second.
Zentaly team proposed architecture design and created proof of concept prototype to assure that expected traffic could be processed in real-time. After design phase our development team in tight cooperation with customer created minimum viable product. And final solution included unit tests integrations tests and performance benchmarks to verify high quality standards.