Operating a high-load mobile application and its backend on a daily basis while continuously adding new features and preventing everything from collapsing is a difficult job. Numerous external services and APIs, continuous refactoring and system optimization makes this process even more error-prone.

We will overview internals of a an app with 13 million users worldwide processing over a million transactions per day. We will cover fault-tolerant system design guidelines with an emphasis on multi-fault tolerant systems. Author will share robust application development best practices and go through common mistakes with detailed explanations.