Senior Software Engineer (Mobile app) in London

Want to build the digital play experiences that bring LEGO products to life? This role helps ensure that strong mobile engineering becomes a foundational capability across our portfolio rather than something solved app by app. By driving architecture, improving development practices, and supporting both modern cross-platform and legacy applications, you’ll give the team the technical strength to move faster and build with confidence. Your work will directly support the broader organization’s ambition to deliver high-quality digital play experiences that children love and families trust.

Responsibilities

• Design, architect, develop, and maintain scalable cross-platform mobile applications for LEGO consumers.
• Lead technical decisions on app architecture, code structure, and platform strategy to support long-term scalability and maintainability.
• Maintain and evolve legacy Unity applications by delivering new features and supporting upcoming LEGO products and experiences.
• Partner closely with UI/UX designers to deliver world-class user experiences with high attention to quality, usability, and visual detail.
• Ensure high engineering standards across code quality, testing, automation, release processes, and application reliability.
• Collaborate with Quality Assurance and Consumer Service teams to identify issues, improve app performance, and enhance customer satisfaction across multiple products.
• Mentor and support other engineers on architectural patterns, scalable development practices, and modern cross-platform frameworks and tools.

Requirements

• Hands-on production experience with Unity or a similar cross-platform mobile app framework (Flutter, React Native, KMP, etc.).
• Strong software engineering fundamentals, including architecture, object-oriented design, testing, debugging, and performance optimization.
• Proven experience designing scalable, maintainable application architecture for consumer-facing mobile apps.
• Experience working with legacy codebases and modernizing existing applications while maintaining stability and compatibility.
• Ability to collaborate effectively across engineering, QA, design, and product teams to deliver high-quality user experiences.
• Strong understanding of code quality practices, automated testing, CI/CD, and release processes for mobile applications.
• Significant software engineering experience, with substantial experience developing mobile or cross-platform consumer applications.

Applications are reviewed on an ongoing basis. However, please note we do amend or withdraw our jobs and reserve the right to do so at any time, including prior to any advertised closing date. So, if you're interested in this role we encourage you to apply as soon as possible.

What’s in it for you?

• Family Care Leave - We offer enhanced paid leave options for those important times.
• Insurances – All colleagues are covered by our life and disability insurance which provides protection and peace of mind.
• Wellbeing - We want our people to feel well and thrive. We offer resources and benefits to nurture physical and mental wellbeing along with opportunities to build community and inspire creativity.
• Colleague Discount – We know you'll love to build, so from day 1 you will qualify for our generous colleague discount.
• Bonus - We do our best work to succeed together. When goals are reached and if eligible, you'll be rewarded through our bonus scheme.
• Workplace - When you join the team you'll be assigned a primary workplace location i.e. one of our Offices, stores or factories. Our hybrid work policy means an average of 3 days per week in the office. The hiring team will discuss the policy and role eligibility with you during the recruitment process.

Children are our role models. Their curiosity, creativity and imagination inspire everything we do. We strive to create a diverse, dynamic and inclusive culture of play at the LEGO Group, where everyone feels safe, valued and they belong. The LEGO Group is highly committed to equal employment opportunity and equal pay and seeks to encourage applicants from all backgrounds (eg. sex, gender identity or expression, race/ethnicity, national origin, sexual orientation, disability, age and religion) to apply for roles in our team. The LEGO Group is fully committed to Children’s Rights and Child Wellbeing across the globe. Candidates offered positions with high engagement with children are required to take part in Child Safeguarding Background Screening, as a condition of the offer. Thank you for sharing our global commitment to Children’s Rights. Just imagine building your dream career. Then make it real. Join the LEGO team today.