Principal Mobile Apps Platform Engineer

Overview

Autotrader is the UK’s leading automotive marketplace, a heritage brand and a tech-focused company. We connect vehicle buyers and sellers and offer a wide range of products beyond cars, including e-bikes and caravans. We strive to untangle the car-buying journey with a people-first approach and a diverse, collaborative culture.

As a Principal Software Engineer, you will play a key role in evolving the in-app experience for the UK’s #1 car buying app. The Autotrader app has been downloaded over 23 million times and serves millions of monthly users, maintaining leading ratings. While the core focus remains the consumer experience, our mobile app teams are instrumental in transitioning Autotrader into a platform where consumers can buy vehicles entirely online.

We have evolved beyond traditional native development by adopting a Server-driven UI architecture. Our team has built a custom client-side framework that renders data, context, and layout configurations served from a federated backend REST API. You will provide technical leadership for this platform, driving architectural scalability, performance, and long-term maintainability across our mobile applications.

We are a close-knit tech community where collaboration and knowledge sharing are central. Regular pair programming, code reviews, and stand-ups ensure engineers stay connected and aligned. As a Principal Engineer, you will have a visible, strategic role in shaping system design and architecture decisions, mentoring teammates, and helping our teams deliver high-quality solutions at scale for one of the UK’s most-used digital products.

• Comfort with spending most development time on backend Kotlin services to maintain and evolve our server-driven UI framework.
• Proven experience with Kotlin Multiplatform (KMP), Gradle, and Spring Boot.
• Extensive experience building and supporting iOS and/or Android applications; proficient with the development toolset on at least one platform (Swift, Xcode, Instruments for iOS; Kotlin, Jetpack, Android Studio for Android).
• Strong understanding of unit testing, RESTful API design, and a commitment to refactoring and regression test automation.
• Experience mentoring and coaching engineers, with a proven ability to share technical expertise and advocate best practices across a team.

Salary £60,000 – £80,000, plus an additional 10% of salary awarded as shares each year. Shares vest over three years with the option to sell or keep. 28 days holiday, plus bank holidays, and comprehensive private medical cover.

We offer a pension scheme (standard contributions 7%, employee 5%), private medical cover, enhanced family leave provisions, a car salary sacrifice scheme, share-save options, and more. We provide 24/7 online GP and dentist access, plus specialist support for fertility, gender dysphoria, menopause, and period care plans.

Our hybrid Working model combines office and home working: spend a minimum of 3 days per week in the office with your team.

We have remote-first periods during summer and winter allowing remote work within the UK and from certain locations abroad.