**About us** You've probably heard of Autotrader, but do you know what we're all about? We're the most trusted, most visited automotive marketplace in the UK. A heritage brand and a tech innovator. We bring together vehicle buyers and sellers to give them real choices. Cars may be what we're best known for but we’re also the place for pretty much everything else on wheels, from e-bikes to caravans. In the automotive world, change is a constant, that’s why we take our job of untangling the complex car-buying journey very seriously. At our core, we’re all about people. We go our own way while embracing diversity and celebrating our differences. We dedicate ourselves to the idea that we work better together. Autotrader is a beautiful, surprising and vibrant place to work. We might not be for everyone, but we could be perfect for you. **About the job** We’re looking for Principal Full Stack Engineers to join us! Our technology teams combine a diverse set of technologies to meet the needs of our users, handling millions of requests a day across over 600 systems. We build these systems with industry standard frameworks and tools, such as React and Angular on the front end and Java, Spring Boot, Cloud SQL and Apache Kafka on the back end. All of this runs on our cutting edge cloud delivery platform, facilitating over 60k releases to production a year. We’re a close-knit tech community where collaboration and knowledge sharing are at the core of what we do. Regular pair programming, code reviews, and stand-ups ensure that our engineers stay connected and aligned. As a Principal Engineer, you’ll play a visible, strategic role in driving system design and architecture decisions, mentoring team members, and helping our teams deliver high-quality solutions at scale. You might think that "Autotrader" means we’re looking for car enthusiasts, but that’s not the case. We’re looking for people who are passionate about technology, thrive in a collaborative environment, and have a genuine curiosity about solving complex problems. **What we’re looking for:** - Strong experience working across the stack, from designing scalable back-end systems to developing responsive front-end applications - You should be comfortable working with Java, Spring Boot and the Java ecosystem / JVM - Ability to architect and design complex, distributed systems that are scalable, maintainable, and performant - Experience with modern front-end technologies (e.g., React or Angular, TypeScript/Modern JavaScript), along with proficiency in building RESTful APIs and web services. - Strong knowledge of relational databases (SQL), along with experience working with document-based storage solutions (e.g., MongoDB) - Experience with Kafka or other event-driven architectures - A structured approach to development and testing (including Test-Driven Development) with a focus on continuous delivery and automation - Proven experience leading and mentoring teams, helping others grow technically while delivering high-impact projects During our application process, you will be asked two questions to help us learn more