Senior Java Developer in London

We’re looking for an experienced backend engineer with a passion for technical excellence and improving user experiences. You’ll join our DAX engineering team, working on our ad server platform and related products that power campaign delivery at scale. This role is based in our Holborn office with hybrid working as part of our Smart Working approach.

As a Senior Java Developer at Global, you will:

• Work across the full lifecycle of our ad-serving products, from discovery and design through to delivery and optimisation. You’ll play a key role in technical decisions, guiding other engineers and helping us ship high-quality, reliable services that support our audio advertising business.

Key Responsibilities

• Product & delivery (35%): Collaborate with product and design to define and deliver backend services and APIs that support great user experiences across our platforms.
• Engineering excellence (35%): Design, build and maintain backend services using modern Java and Spring Boot, applying clean code principles, contract-first design and robust automated testing.
• Leadership & collaboration (30%): Guide and mentor engineers in the team, champion best practices, and work closely with other engineering and operations teams to ensure the reliability, performance and scalability of our live services.

What You’ll Love About This Role

• Think Big: Work on complex technical challenges that directly impact how we deliver and optimise audio advertising to millions of listeners.
• Own It: Take ownership of services and features, from architecture and implementation through to monitoring, iteration and continuous improvement.
• Keep it Simple: Help simplify complex systems, designing clear, maintainable solutions that allow the team to move quickly and safely.
• Better Together: Be part of a collaborative engineering culture that values pairing, code reviews, shared decision-making and learning from each other.

What Success Looks Like

• Contributed to key features on our booking and ad-serving platforms that improve how we deliver and manage campaigns.
• Led or significantly influenced technical design discussions and architecture decisions within the team.
• Brought a strong understanding of our core business challenges and how our systems support them, proposing and delivering iterative improvements.
• Improved reliability, performance or cost efficiency of at least one key service through targeted technical changes.
• Helped enhance our testing, deployment or monitoring practices, raising the overall quality and robustness of our services.
• Built positive relationships with product, design and other engineering teams.

What You’ll Need

• Backend engineering expertise: Strong experience with Java and modern Spring / Spring Boot, applying clean code and contract-first design to build reliable services.
• Platform & tooling knowledge: Hands-on experience deploying and running services in containerised environments (e.g. Docker, Kubernetes), with a commitment to automated testing across different layers.
• Collaboration & communication: Ability to work effectively in a cross-functional team, partnering with product, design and fellow engineers to deliver impactful solutions.
• Ownership & problem solving: A self-driven, solutions-focused mindset with attention to detail, able to take problems from concept through design, implementation and production rollout.
• Desirable experience: Experience with AWS and infrastructure-as-code tools (e.g. Terraform), CI/CD tooling (e.g. Jenkins, GitHub Actions), modern Java language features, and good practices for production support and incident management.