Principal Mobile Apps Platform Engineer

AutoTrader UK; Manchester; Hybrid; GBP 60,000 - 80,000; Full time

Benefits offered by this job

Shares program

Private medical cover

Pension scheme

Car salary sacrifice

Share-save options

Hybrid working

Remote periods abroad

Annual leave 28 days

Job summary

AutoTrader UK is seeking a Principal Software Engineer to lead the evolution of our UK’s #1 car buying app backend and mobile experiences. You will steer server-driven UI architecture and scalable systems that power millions of users.

You’ll mentor engineers, shape best practices, and collaborate with product and platform teams to deliver high-quality, maintainable code at scale. This role combines hands-on coding with technical leadership in a hybrid working model.

Qualifications

• Experience with backend Kotlin services and server-driven UI.
• Proven experience with Kotlin Multiplatform, Gradle, and Spring Boot.
• Experience building mobile applications on iOS/Android.
• Strong unit testing and REST API design.
• Experience mentoring engineers and sharing best practices.

Responsibilities

• Provide technical leadership for the platform and architecture.
• Drive scalability, performance, and long-term maintainability across mobile apps.
• Mentor and coach engineers to raise the team's capabilities.
• Collaborate with product and platform teams to deliver high-quality solutions at scale.

Skills

Kotlin

Kotlin Multiplatform

Gradle

Spring Boot

Mobile development

iOS tools

Android tools

REST API design

Unit testing

Mentoring

Tools

Xcode

Instruments

Android Studio

Jetpack

Job description

About Autotrader

You’ve probably heard of Autotrader, but do you know what we’re all about?

We’re the UK’s leading automotive marketplace, a heritage brand, and a tech darling of the stock market. We bring together vehicle buyers and sellers to give them real choices. Cars may be what we'rebest 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 role

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 apphas been downloaded over 23 million times and consistently serves over 3 million monthly users,maintainingleading ratings of 4.8/5 on the App Store and 4.7/5 on Google Play. While our core focusremainson the consumer experience, ourmobile appsteam are currently instrumental in transitioning Autotrader into a platform where consumers can buy vehicles entirely online.

We’veevolved beyond traditional native development approaches by adopting a Server-driven UI architecture. Our team has developed a custom client-side framework that dynamicallyrendersdata, context, and layout configurations served up from a federated backend REST API. In this role, you will provide technical leadership for this platform, driving architectural scalability, performance, and long-term maintainability across our mobile applications.

We’rea 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’llplay a visible, strategic role in driving system design and architecture decisions, mentoring team members, and helping our teams deliver high-quality solutions at scale for one of the UK's most used digital products.

What we're looking for

• You should be comfortable with the fact thatmostofyour development time will be spent working on our backend Kotlin services tomaintainand evolve ourserver-drivenUIframework.
• Proven experience with Kotlin Multiplatform (KMP), Gradle, and Spring Boot.
• Experience building and supporting mobile applications; proficient user of the development toolset on at least one of these platforms (Swift, Xcode, and Instruments for iOS; Kotlin, Jetpack, Android Studio for Android).
• Strongunderstanding 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 technicalexpertiseandadvocatebest practices across a team.

Benefits and more

• We’re offering a salary of £60,000 – £80,000, plus an additional 10% of your salary awarded to you in shares each year.
• These awarded shares will become yours in yearly instalments over the next three years, and you can choose to either sell them or keep them as shares.
• And you'll receive 28 days holiday, plus bank holidays and comprehensive private medical cover.
• That’s not all.
• You’ll be enrolled in our pension scheme, where our standard contributions are 7% and employee contributions are 5%.
• We also have comprehensive private medical cover, enhanced family leave provisions, a car salary sacrifice scheme, share-save options, and much more.
• On top of all that, our hybrid model, Connected Working, combines the best of both worlds – office and home working.
• You’ll spend a minimum of 3 days a week in the office with your team, focused on collaboration and connection.
• Additionally, we have our remote-first periods at set times during summer and winter.
• During these periods, you can work remotely anywhere in the UK and from certain locations abroad.

Discover more about our hiring processand exploreour Engineering Blog.

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