SeniorAISoftwareEngineer–ModelTraining(f/m/d)

OUR MISSION Aleph Alpha is one of the few companies in Europe doing serious foundation model pre- and post-training. We're building models that have general-purpose capabilities, and specifically excel at addressing the needs of our customers. We're looking for exceptional Software Engineers to join our model training team. Most of the team is based in Heidelberg . TEAM CULTURE At Aleph Alpha, we foster a culture built on ownership, autonomy, and empowerment. Teams and individual contributors are trusted to take responsibility for their work and drive meaningful impact. We maintain a flat organizational structure with efficient, supportive management that enables quick decision-making, open communication, and a strong sense of shared purpose. We believe a strong engineering culture is the key to model training success. We like Extreme Programming and favor trunk-based development. We often mob-program, which keeps us aligned and means we always learn from each other. ABOUT THE ROLE As a Software Engineer in Model Training, you'll work across our full stack. Some weeks you might be optimizing how training loads are scheduled on our cluster and making the pipeline more robust and performant so we can iterate faster. Other weeks, you'll be enabling large-scale code execution for reinforcement learning. And at other times, you might dig deep into our evaluation codebase to lift inference throughput on evals. No two days are the same. Things move fast, and your ability to focus and prioritize is what lets you unblock the team day-to-day while designing the high-quality tooling and infrastructure that speeds us up long-term. We're still building out our training pipeline and infrastructure. Some pieces exist, some don't, and you'll have real influence on what gets built and how. Your work directly shapes how quickly we can experiment and improve our models. YOUR RESPONSIBILITIES - Co-own the training pipeline end-to-end. Design, build, and maintain the infrastructure and