Principal Full Stack Engineer - Full or Part Time

Auto Trader

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'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 role We're looking for Principal Software Engineers to help us build a technology platform for more than just the needs of Autotrader.co.uk. Utilising our public-facing web services and additional external data sources means that we'll be able to power businesses across the automotive industry. Spring Boot, Apache Solr, Cloud SQL and Apache Kafka power our platform and process millions of events per day. As a team, our software developers are responsible for ensuring service availability and responsiveness continue to improve. They work on systems that handle thousands of requests per second, with sub-100 millisecond response times, servicing requests from over 50 client applications. Our tech community value collaboration and teamwork. Interactions such as pairing, code reviews and regular stand-ups mean our software developers stay connected. Our principal engineers play a visible and vital role, are comfortable talking about system design and architecture, and know how to get the best out of our teams and our technology platforms. You might assume that our name, "Autotrader," means you need to be a car enthusiast to work here. But that's not the case. We're looking for people who are passionate about their work and thrive in a collaborative environment. WHAT WE'RE LOOKING FOR * A thorough understanding of Java and the JVM  * Knowledge of server-side frameworks such as Spring * Web application design and RESTful API know-how * A structured approach to programming and testing, such as TDD * Proven experience mentoring, coaching and sharing technical expertise  * Architectural and system design knowledge   * Experience leading and delivering technical projects * SQL/Relational databases * Document/Map based storage (eg: MongoDB) * Working with Kafka messaging/streaming 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.   We always want to give you the support you need and help prioritise your wellbeing, that’s why we provide access to 24/7 online GP and dentist, as well as specialist support for assisted fertility, gender dysphoria, menopause, period care plans and lots 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 process and explore our Engineering Blog. #LI-EC1 #LI-Hybrid

Auto Trader

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'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 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 app has been downloaded over 23 million times and consistently serves over 3 million monthly users, maintaining leading ratings of 4.8/5 on the App Store and 4.7/5 on Google Play. While our core focus remains on the consumer experience, our mobile apps team are currently instrumental in transitioning Autotrader into a platform where consumers can buy vehicles entirely online.  We’ve evolved beyond traditional native development approaches by adopting a Server-driven UI architecture. Our team has developed a custom client-side framework that dynamically renders data, 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’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 for one of the UK's most used digital products.   WHAT WE'RE LOOKING FOR * You should be comfortable with the fact that most of your development time will be spent working on our backend Kotlin services to maintain and evolve our server-driven UI framework.  * 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).  * 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.   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.   We always want to give you the support you need and help prioritise your wellbeing, that’s why we provide access to 24/7 online GP and dentist, as well as specialist support for assisted fertility, gender dysphoria, menopause, period care plans and lots 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 process and explore our Engineering Blog. #LI-EC1 #LI-Hybrid

Allica Bank

About Allica Bank Allica is the UK’s fastest growing company - and the fastest-growing financial technology (Fintech) firm ever. Our purpose is to help established SMEs, one of the last major underserved opportunities in Fintech. Established SMEs are the backbone of local communities - representing over a third of our economy - yet have been largely neglected both by traditional high street banks and modern fintech providers. Technology sits at the centre of Allica. We design and build the platforms that power the bank, working closely with every part of the business to deliver real impact for customers. Our teams move quickly, focus on outcomes, and take ownership from concept through to delivery. We solve complex problems, modernise processes, and enable the business to scale with confidence. What makes us different is the level of influence and autonomy engineers have. We work without the weight of legacy systems, which means we can focus on building for the future. Everyone contributes ideas and helps shape how we operate, and roles evolve as the organisation grows. This is a place for people who want to have a tangible impact and do their best work in a modern, collaborative environment. Role Description The Full Stack Engineer contributes to the design and delivery of products within a squad, helping to build secure, reliable, and accessible software while maintaining high engineering standards and a good developer experience. You will use your skills in Spring Boot microservices (Kotlin/Java) and modern web technologies (React/TypeScript) to deliver features across the stack. Our backend services run as containerised applications on Azure Container Apps, and our web applications are deployed via Azure Static Web Apps; you will help ensure the services and applications you work on are production-ready and make effective use of these platforms. You will contribute to good engineering practices in observability, CI/CD, security, performance, and accessibility, helping systems meet the standards expected of a UK bank. You will contribute to Architecture Decision Records (ADRs) and follow organisation-wide patterns and standards. You are hands-on and collaborative: you help design features, write code, review changes, and work closely with engineers, Product, and Design to deliver valuable outcomes. You use approved GenAItools such as GitHub Copilot, Codex or Claude Code responsibly to improve productivity and quality, while validating outputs carefully. Success in this role is measured by the consistent delivery of high-quality features, contribution to reliable and maintainable systems, improvements to the codebase and operational health of services, and your growth in technical capability and ownership. Principal Accountabilities: Contribute to the end-to-end design and delivery of features across the full stack using: * Backend: Kotlin/Java Spring Boot microservices, containerised and deployed on Azure Container * Apps, exposing REST/OpenAPI APIs and integrating with other services and data stores. * Frontend: React/TypeScript, shared design system components, and agreed architectural patterns, deployed on Azure Static Web Apps. * Contribute to technical design discussions and help produce clear ADRs for significant decisions, documenting context, options, trade-offs, and outcomes in line with organisation standards. * Support the squad’s services in production by contributing to SLOs and operational metrics, monitoring systems, responding to incidents, and helping to reduce recurring issues and improve reliability. Apply secure and compliant engineering practices: * Follow secure coding standards and contribute to threat modelling activities. * Ensure logging, audit trails, and data handling meet regulatory and privacy requirements. * Ensure accessibility standards are met in user-facing features. * Help strengthen observability and operational excellence within the squad by contributing to metrics, tracing, logs, dashboards, runbooks, and alerts, and using them effectively in day-to-day engineering work. * Contribute to improvements in developer experience, including CI/CD pipelines, test strategy, local development workflows, and release practices, in line with wider engineering standards and cloud deployment patterns. Use AI-assisted engineering responsibly: * Use approved tools like GitHub Copilot, Codex or Claude Code to improve speed, quality, and consistency. * Validate and refine AI-generated code to ensure correctness, maintainability, and compliance. * Share feedback and effective practices with the team. * Collaborate closely with Product Managers and Designers to understand requirements, shape practical solutions, and deliver work aligned to product goals and timelines. * Maintain high standards of code quality, testing, documentation, and maintainability across the squad’s codebase, while helping to reduce technical debt. * Support other engineers through pairing, code review, and knowledge sharing, contributing positively to the growth and effectiveness of the squad. Personal Attributes & Experience * Experience building and operating Spring Boot microservices in Kotlin or Java, including REST APIs, integrations, and containerised deployments on a major cloud platform (Azure preferred; AWS or Google Cloud also relevant). * Good knowledge of React and TypeScript, with practical experience building accessible, maintainable, and performant user interfaces. * Ability to design and deliver well-structured features within an existing architecture, with an understanding of trade-offs around scalability, maintainability, and delivery pace. * Good understanding of distributed systems fundamentals appropriate to microservices, such as resilience, latency, and failure handling. * Good understanding of secure coding practices, privacy considerations, and security expectations for production systems. * Experience with testing, CI/CD pipelines, and observability tooling; familiarity with Azure DevOps Pipelines and Azure deployment services is beneficial. * Ability to improve code quality through refactoring, clearer abstractions, and maintaining sensible boundaries between modules and services. * Experience collaborating through code review, pairing, and technical discussions to help improve team outcomes. * Experience using GenAI tools such as GitHub Copilot, Codex or Claude Code to improve productivity and code quality, with a clear understanding of their limitations and the need for review and validation. * Strong communication and collaboration skills, with the ability to work effectively with engineers, Product Design & other stakeholders. Working at Allica Bank At Allica Bank we want to ensure our employees have the right tools and environment in which to succeed in their role and in support of our customers. Our employees are at the heart of everything we do, so our benefits are designed with you in mind: * Full onboarding support and continued development opportunities * Options for flexible working * Regular social activities * Pension contributions * Discretionary bonus scheme * Private health cover * Life assurance * Family friendly policies including enhanced Maternity & Paternity leave Don’t tick every box? Don’t worry if you don’t have all the skills or requirements listed on the job description. If you think you’ll be a good fit, we’d still love to hear from you! Flexible working We know the ‘9-to-5’ isn’t right for everyone. That’s why Allica Bank is fully committed to flexible and hybrid working. Please let us know what is best for you and, if we can, we will do our best to accommodate. Diversity We’re a diverse bunch here at Allica, with all kinds of experiences, backgrounds and lifestyles. Our openness and differences make us stronger, and we want everybody to feel comfortable bringing as much of themselves to work with them as they like.