Principal Mobile Engineer - Core Tech

Office location: Cambridge, UK – This position offers flexible working options, including predominantly remote work. Applicants should be based (or willing to relocate) within a comfortable commuting distance of our office to attend onsite as required. Are you an experienced mobile engineer with a track record of leading large-scale technical initiatives and shaping mobile architecture across complex products? As a Principal Mobile Engineer, you’ll take ownership of mobile engineering direction across critical player-facing systems. From initial player onboarding through to ongoing engagement, you’ll define and deliver scalable, secure mobile solutions that support key journeys across the RuneScape franchise. Operating across multiple teams and domains, you’ll drive technical strategy, guide architectural decisions, and ensure delivery of high-quality mobile systems that meet the demands of a global player base. What you’ll be doing: Own and drive mobile engineering initiatives across multiple projects, ensuring alignment with product goals and long-term technical strategy. Define and evolve mobile architecture across iOS and Android, ensuring scalability, performance, and maintainability. Lead the delivery of complex technical solutions, coordinating across teams and managing dependencies at a system level. Establish and uphold engineering standards across mobile development, including code quality, testing, and deployment practices. Identify and drive improvements to systems, services, and engineering processes to support reliable, scalable delivery. Work closely with backend, product, and platform teams to ensure seamless integration across services and user journeys. Guide technical decision-making, balancing short-term delivery with long-term system health and evolution. What we’re looking for: Proven track record leading large-scale mobile engineering initiatives within production environments. Deep expertise in native mobile development across iOS (Swift / Objective-C) and Android (Kotlin / Java). Strong experience defining and evolving mobile architecture integrated with backend microservices. Strong understanding of the software development lifecycle, including CI/CD, testing, and release practices. Experience operating across teams to manage technical direction, dependencies, and delivery outcomes. Advanced debugging, performance optimisation, and system-level problem-solving capability. Experience with C++ is an advantage. What we offer: When you join Jagex you can look forward to a generous Perks & Benefits package including: Private Healthcare, including Dental Plan. Discretionary annual performance bonus. Minimum 6% Pension contributions. Life Insurance. Enhanced family leave policies from day 1. Flexible working hours. 25 days annual leave + Bank holidays & the option to buy/sell holidays + so much more! About Jagex We are Jagex: The RuneScape Company. Home to one of gaming’s most enduring success stories. We create deep, community-powered games with worlds that evolve, inspire, and endure. Our flagship MMORPG franchise, RuneScape, has welcomed over 300 million player accounts, inspiring generations of players across PC and mobile for 25 years. As we begin our 26th year, we are accelerating our strategy to expand RuneScape into a broader ecosystem of forever games and connected experiences, grounded in a renewed commitment to integrity and fair play. This includes the reduction of monetisation mechanics, as well as the launch of RuneScape: DragonWilds into Steam Early Access in 2025, representing a major step in building a multi-genre future for the RuneScape universe. We remain focused on building enduring worlds, empowering player-led innovation, and laying the foundations for the boldest era in RuneScape’s history. For more information, visit www.jagex.com . Headquartered in Cambridge, United Kingdom, we are home to passionate creators, storytellers, engineers, and even a few dreamers, all united by a single mission to shape the future of online worlds and empower players to make them their own. We’re looking for people to join us who share our ambitions and values. We foster an inclusive workplace built on trust, autonomy, and a shared passion for creating experiences that inspire our communities. Our values guide everything we do: We Embrace Fellowship by collaborating and sharing openly. We Hone our Craft by always learning and improving; We Honour our Vows by being honest and transparent; We are our Customers’ Heroes by striving to understand our team & player needs, and We Seize The Day by making the most of every opportunity. Join us. The next era of RuneScape and the next chapter of Jagex: The RuneScape Company starts now. We are committed to providing equal opportunities and creating an environment where everyone can thrive. We welcome applications from all backgrounds, and we recruit, develop, and promote based on merit and ability. If you require any reasonable adjustments to support you during the recruitment process, please let us know when you’re invited to interview.