In this presentation, I'll give you an overview of how Rspamd, our open-source project, has evolved over the years. We'll explore the key choices we made in designing it and the challenges we faced while making it grow. I'll also show you real examples of how we've kept up with modern practices like Continuous Integration, extensive testing (including AI assisted testing), support for containers and different systems. At the same time, I'll discuss vital elements such as keeping things compatible with older versions and smoothly working with the existing code, since the core of Rspamd is written in plain C.