Are you frustrated working with large, legacy and potentially lethal code bases? We were frustrated too, but in 4-5 years of time, we replaced A (front-end) and B (back-office) system with ~150 microservices. From the days of no tests and clumsy deployment process, we moved to each service with unit tests, CI and deploying with a bot. With the business buying in the process, we enabled the company to reach new heights. This talk reveals that journey and the things we learned along the way.