Senior Backend Engineer (f/m/x)

Your Mission This is a company built for growth. At exmox, you’ll work on real systems on a big scale. We build high-performing consumer products used by millions of users, operating in a highly competitive, global mobile gaming ecosystem. Our products are data-driven by design - powered by event-driven architectures, complex business logic, and fast feedback loops. Decisions are informed by data, experimentation, and measurable impact, not gut feeling. We’re scaling fast and building one of the most exciting innovations in mobile gaming: a rewarded user engagement and user acquisition platform. We help mobile game publishers not only acquire new users, but also keep players engaged through rewarding experiences. That means distributed systems, evolving architectures, and problems that don’t have textbook answers. As Senior Backend Engineer (f/m/x) you won’t just be “coding tickets” or maintaining legacy systems. We look for people with an engineering mindset and entrepreneurial ownership - you build it, you own it. You’ll work close to product and data, take responsibility for what you ship, and see the impact of your work in production. If you’re excited by complex systems, high traffic, data-driven decisions, and the chance to grow by solving challenging problems, we want to hear from you. What You’ll Own System architecture & backend engineering You architect and build high-scale backend systems that power real-time decision-making, ad delivery, and performance tracking. You ensure systems are reliable, maintainable, and scalable under high traffic, applying best practices in distributed systems, queues, and event-driven architectures. API design & integration You design efficient APIs and services that serve internal teams and external partners with low latency and high reliability, including REST and GraphQL endpoints. You integrate with third-party platforms, MMPs, and analytics tools to maximize campaign effectiveness. Performance, scaling & observability You ensure high performance under load using profiling, caching strategies, and horizontal scaling. You contribute to containerized deployments and observability with Docker, Kubernetes, and modern monitoring stacks to maintain system reliability and visibility. Mentorship & technical leadership You mentor and guide engineers through complex technical challenges, architecture reviews, and clean, scalable design. You foster a culture of technical excellence, collaboration, and outcome-driven engineering. Cross-functional impact You collaborate with product and data teams to deliver features that directly influence campaign effectiveness and advertiser ROI. Your work drives measurable business outcomes and sets the bar for system performance and reliability. What You Bring Proven backend expertise 5+ years of backend engineering experience, with at least 2+ in high-volume, data-rich environments. Strong Python expertise, with production experience in FastAPI, Flask, or similar frameworks. API & distributed systems knowledge Deep understanding of API design and backend system integration, including REST and GraphQL. Experience with distributed systems, queues (Kafka, RabbitMQ), and event-driven architectures. Performance & scaling focus Strong performance tuning and scaling skills, particularly for latency-sensitive, high-throughput systems. You think in systems and optimize holistically for efficiency and reliability. Cloud & container experience Experience with Docker, Kubernetes, and cloud infrastructure, ensuring smooth deployment, orchestration, and observability. Analytical & business-aware mindset You solve problems holistically, understand system-wide impacts, and make decisions that balance technical excellence with business outcomes. Communication & collaboration Strong communicator, comfortable explaining complex technical concepts to cross-functional teams, product managers, and business stakeholders. AdTech familiarity Experience with ad serving logic, tracking systems, fraud prevention, or real-time bidding is a significant advantage. What You Can Expect Ambitious people, real ownership. Work with driven people who challenge each other openly and take full ownership of meaningful parts of the business. A company that prioritizes growth, performance, and impact. Comfort isn’t the goal here, progress is. We set a high bar and focus on delivering real results. A highly ambitious environment with a clear goal. Building the next European tech challenger is not just an idea, it is our mission. Everything we do is driven by the ambition to compete at the highest level and win. Direct exposure to leadership and real decision-making. You’ll work closely with experienced leaders, contribute to strategic discussions, and see how decisions shape the business in real time. Perks that help you focus on what matters. Transport subsidy, learning budget, wellness and gym, workation, bi-weekly team lunches, and more. The perks are great, but the real reason people join and stay is the challenge, the ownership, and the drive to win together. Please note: this is not a remote only position, we offer you a flexible hybrid model here in Hamburg, Germany - working from home on Mondays & Fridays, coming to the office on Tuesday, Wednesday & Thursday!