Lead Data Scientist

Overview We're hiring a Staff ML & Data Engineer to own and evolve Preply's ML platform. You will design the systems that enable our ML teams to move from research to production seamlessly – at scale, across clouds, and with minimal friction. This role blends strategic platform architecture with deep hands‑on engineering. You'll partner with Engineering and ML leadership to define standards, introduce new tooling, and eliminate barriers to deploying reliable, cost‑efficient, and observable ML systems. Your mission Lead the design and implementation of Preply's ML platform architecture: from experiment tracking and artifact management to scalable model deployment. Drive cloud‑native solutions for distributed training and inference, including GPU‑based training environments, autoscaling, and rollout strategies. Own technical direction for CI/CD for ML, incorporating testing, validation, and performance checks into every deployment pipeline. Embed observability best practices across ML workflows: metrics, alerts, drift detection, lineage. Act as a multiplier across engineering: mentoring, influencing standards, and de‑risking complex technical decisions. Partner with ML Leads and Product teams to align platform direction with experimentation velocity, cost‑efficiency, and user impact. Design and lead building ML services that are modular, testable, and monitored from day one. Contribute to LLM platform capabilities, including RAG pipelines, latency‑optimized inference, and prompt experimentation frameworks. Qualifications 8+ years of engineering experience in large‑scale Data/ML platforms, with proven ability to architect and scale production‑grade systems supporting dozens of ML use cases. Deep knowledge of cloud services and strong understanding of end‑to‑end ML workflows, including versioning, monitoring, and performance benchmarking. Experience working with scientists and building enabling tools for them. Excellent communication and influence across cross‑functional teams, motivated by product impact. Mentoring and coaching ML engineers. Familiarity with LLM frameworks (LangChain, LlamaIndex), vector stores, and retrieval infrastructure. Company Values Care to change the world – We are passionate about our work and care deeply about its impact to be life changing. We do it for learners – For both Preply and tutors, learners are why we do what we do. Every day we focus on empowering tutors to deliver an exceptional learning experience. Keep perfecting – To create an outstanding customer experience, we focus on simplicity, smoothness, and enjoyment, continually perfecting it as every detail matters. Now is the time – In a fast‑paced world, it matters how quickly we act. Now is the time to make great things happen. Disciplined execution – What makes us disciplined is the excellence in our execution. We set clear goals, focus on what matters, and utilize our resources efficiently. Dive deep – We leverage business acumen and curiosity to investigate disparities between numbers and stories, unlocking meaningful insights to guide our decisions. Growth mindset – We proactively seek growth opportunities and believe today's best performance becomes tomorrow's starting point. We humbly embrace feedback and learn from setbacks. Raise the bar – We raise our performance standards continuously, alongside each new hire and promotion. We build diverse and high‑performing teams that can make a real difference. Challenge, disagree and commit – We value open and candid communication, even when we don't fully agree. We speak our minds, challenge when necessary, and fully commit to decisions once made. One Preply – We prioritize collaboration, inclusion, and the success of our team over personal ambitions. Together, we support and celebrate each other's progress. Benefits An open, collaborative, dynamic and diverse culture. A generous monthly allowance for lessons on Preply.com, Learning & Development budget and time off for your self‑development. A competitive financial package with equity, leave allowance and health insurance. Access to free mental health support platforms. The opportunity to unlock the potential of learners and tutors through language learning and teaching in 175 countries (and counting). #J-18808-Ljbffr