Five years ago, Kiwi.com began its story as a super fast growing startup. Today, we have almost 2 400 employees with more than 400 people in the engineering team. During this time, everything changed several times, including our people, company, vision, goals, and last but not least our codebase and stack. It wouldn’t be possible to handle this growth without following the latest trends in technology and code principles. In this talk, I will tell you about our codebase and stack: how it changed in the last couple of years, where we want to push it in the future, what tools we use, what we learned that works, and what helped us to maintain rapid growth. I will share with you the lessons learned and my experiences from almost 4 years in this company.