Everyone talks about code "scalability" and "maintainability", but I remember struggling to come up with a such a project structure when I got started in tech. I needed a practical real-world example with best practices. Years later, I built Custodian - a large, complex platform. Our developers team grew in size seamlessly. I share some of my learnings and shortcomings. I will walk through our codebase structure, how I learned from open source projects, and crucially, how we leveraged typescript and atomic design - a match made in heaven.