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 a principal-level mobile engineer ready to set the technical direction for mobile across one of the world's most iconic gaming franchises?

As a Principal Mobile Engineer in our Player Gateway team, you'll own the mobile architecture and engineering strategy that shapes how players first experience Jagex titles - from their very first visit through to becoming active members of our game communities. This is a role with genuine organisation-wide impact: your technical decisions will set the standards and patterns that engineers across multiple teams build on.

You'll lead the most complex, high-stakes mobile initiatives from concept through to production, influence engineering strategy beyond your immediate team, and raise the bar for mobile engineering across the discipline - all while helping the next generation of engineers grow.

What you'll be doing:

• Own the technical direction and architecture for mobile initiatives within the Player Gateway team, influencing engineering standards and strategy across the wider discipline.
• Lead the delivery of our largest, most complex mobile initiatives - breaking down ambiguity, de-risking delivery, and defining the approaches other engineers follow.
• Drive long-term improvements to systems, services, and ways of working that extend well beyond a single team, shaping the future of mobile at Jagex.
• Contribute across the full Software Development Lifecycle, delivering secure-by-design, production-ready code backed by automated testing, peer review, and reliable deployment.
• Lead build/buy evaluations and architectural proposals, ensuring technical solutions meet both product needs and Jagex's engineering standards.
• Raise the engineering bar across the mobile discipline through coaching, mentoring, and championing best practice - multiplying the effectiveness of those around you.
• Participate in an on-call rotation to troubleshoot and resolve production issues when required.

• Demonstrable expertise in native mobile development across both iOS (Swift / Objective-C, Xcode, Instruments) and Android (Kotlin / Java, Android Studio, profilers), with a deep understanding of OS-level constraints including app lifecycle, permissions, backgrounding, and store policies.
• Proven ability to set and own technical direction and mobile architecture across multiple teams or an engineering discipline.
• Track record of leading large, ambiguous, or cross-team technical initiatives from concept through to production, with minimal direction.
• Demonstrated experience influencing technical strategy and building consensus across teams and senior stakeholders without direct authority.
• Proven ability to raise engineering standards across a discipline through coaching, technical leadership, and championing best practice.
• Strong experience with automated testing, CI/CD systems (e.g. Git, Bitbucket Pipelines, Bamboo), debugging, profiling, and mobile performance optimisation at scale.
• Experience with A/B testing frameworks, analytics SDKs, and collaborating with UX designers to deliver streamlined player experiences is advantageous. Experience with C++ and game systems is a plus.

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!

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.