Junior Java Developer

Your Role: Junior Java Developer – DAX Exchange

Are you an early-career engineer who wants to build high-performance systems that power digital advertising at scale?

As a Junior Java Developer – DAX Exchange at Global, you’ll join a small, focused team building performance-critical services in modern Java. You’ll work on the matching engine that connects advertisers with outdoor screens and, over time, live radio and on-demand audio. You’ll contribute to production code from day one and learn how real-time systems are designed, built and run in the cloud.

Key Responsibilities

• Backend development (40%): Contribute to the DOOH Scheduler and DAX Exchange, delivering features, fixes and enhancements across the platform using modern Java.

• Quality and reliability (20%): Write clean, well-tested and maintainable code that meets the team’s standards for performance, resilience and observability.

• Operational support (20%): Help monitor, troubleshoot and maintain production services, gaining experience with supporting real-time, always-on systems.

• Learning and collaboration (20%): Pair with senior engineers, participate in code reviews and technical discussions, and support continuous improvement in how the team works.

What You’ll Love About This Role

Think Big: Help build the matching engine that powers programmatic advertising across outdoor screens in the UK, with growing opportunities across live radio and digital audio.

Own It: Ship code that runs in production, take responsibility for your changes and see the direct impact of your work on a critical platform.

Keep it Simple: Learn to design clear, focused services and straightforward solutions to complex performance and scalability challenges.

Better Together: Work in a small, supportive team where you’ll receive mentoring, regular feedback and a clear path from junior to mid-level.

What Success Looks Like

In your first few months, you’ll have:

• Contributed working, well-tested code to the matching engine and related services.

• Gained a solid understanding of the DAX platform, its data flows and performance requirements.

• Learned and applied the team’s development practices, tooling and deployment workflows.

• Helped support production systems, including monitoring, debugging and incident follow-up.

• Built strong working relationships with your teammates through pairing, reviews and regular collaboration.

What You’ll Need

• Technical foundations: Experience from a Computer Science (or similar) degree or equivalent practical background, with a strong understanding of core data structures and algorithms.

• Java and OOP fundamentals: Knowledge of Java and core object-oriented concepts such as inheritance, composition and common design patterns.

• Engineering practices: Familiarity with Git, basic Unix/Linux commands and working within an agile software development environment.

• Attention to detail: A careful, methodical approach to writing, reviewing and testing code.

• Growth mindset: Curiosity about how software interacts with hardware and networks, and an interest in learning more about cloud infrastructure, containerisation and real-time systems.

• Nice to have (not essential): Interest in low-level performance, networking or systems programming; exposure to AWS or other cloud platforms and/or containerised environments; curiosity about digital advertising, media or high-throughput real-time platforms.