Machine Learning Engineer

Senior Machine Learning Engineer — AdTech & Recommendation SystemsWhat's On OfferCompetitive salary, depending on experience and seniorityHybrid working model based in Hamburg, Germany, with relocation and visa support availableInternational, English-speaking environmentGenuine technical ownership on large-scale deep learning, recommendation, and real-time serving systemsStrong opportunities for career growth within a fast-moving Data Science organizationThe Role We are supporting a leading mobile advertising platform, operating at massive scale across hundreds of millions of users, in growing their Machine Learning Engineering team. You'll be working on real-time bidding optimization, ad ranking, and conversion modeling — systems that make live decisions in milliseconds at massive scale.Build and optimize deep learning models for recommendation, ranking, and biddingDesign and deploy real-time, low-latency inference systems serving live production trafficDevelop scalable machine learning solutions using modern deep learning techniquesWork with massive production datasets to improve model performance and business outcomesOwn models end-to-end — from research and experimentation through production deployment and A/B testingCollaborate closely with engineering and product teams to translate ML into measurable business impactWhat We're Looking For5+ years of experience in Data Science, Machine Learning Engineering, or Applied ScienceStrong hands-on experience with deep learning frameworks (PyTorch and/or TensorFlow)Experience with large-scale recommendation systems, ranking, or personalization modelsExperience building and deploying real-time, low-latency production ML systems (online inference, live serving) — this is essentialStrong Python and SQL skills, with experience integrating models into production pipelinesExperience in AdTech, mobile gaming, e-commerce, or a similarly large-scale consumer platformExperience with real-time bidding or programmatic advertising is a strong plusThis role is focused on recommendation, ranking, and bidding systems — not conversational AI, RAG, or LLM application engineering. If your recent work has been primarily LLM/GenAI/chatbot development without a strong recommendation systems foundation, this likely isn't the right fit.ApplyIf you're passionate about building large-scale, real-time machine learning systems in a fast-paced, high-impact environment, we'd love to hear from you. Apply today or get in touch for a confidential discussion.