Senior Backend Engineer (f/m/x)

Job description

Your Mission This is a company built for growth. When you join exmox, you're stepping onto a global, highly competitive playing field, solving real problems in environments that push you beyond your comfort zone. You'll work on real systems at a big scale, building high-performing consumer products used by millions. We move fast, cut the noise, and focus on what actually matters, because in our industry, speed wins. We're rapidly scaling one of the most exciting innovations in mobile gaming: a rewarded user engagement and acquisition platform that helps publishers acquire and retain players through rewarding experiences. Our products are data-driven by design, powered by event-driven architectures, complex business logic, and quick feedback loops, with decisions informed by data and experimentation, not gut feeling. 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, working close to product and data and seeing the impact of your work in production. At exmox, we're embracing AI as part of how we work, not just what we build. We use AI tools to work smarter, cut down on repetitive tasks and spend our time where it actually moves the needle. If that mindset speaks to you, you'll fit right in. 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. How We Win Speed is the feature. Speed beats rocket science. We move fast, test fast, and multiply our pace with AI, because action creates information and small wins compound. A fast failure is a lesson we learn from, a slow one is a problem we can't afford. Focus on the essential. Done is better than perfect. We stay focused on what actually moves us forward and protect people's time from anything that doesn't. We're direct in how we communicate too, no rambling, no unnecessary detail. See it. Own it. Solve it. The first to see it is best placed to fix it. We're not a place for comfort, we're a place for doers. "Not my job" isn't in our vocabulary, if you spot something, you help make sure it gets solved. Respect others. Trust multiplies. Respect is non-negotiable. We disagree with ideas, never with people. Trust here is built the same way it is anywhere, through consistency, a thank you, a moment of listening, and owning your mistakes. 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!