Senior AI R&D Engineer – Pre-training Data (f/m/d)

Aleph Alpha

OUR MISSION Aleph Alpha is one of the few companies in Europe doing serious foundation model pre-training. Our customers - in finance, manufacturing, public administration - need models that understand German, meet European regulatory requirements, and work reliably in high-stakes settings. We're building that in Heidelberg. We are hiring a Senior AI R&D Engineer focused on Performance to grow our pre-training efficiency team. If you are excited about making models fast, this is the role for you! 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. ABOUT THE ROLE: You will engineer the systems required to train foundation models at scale. Your objective is to maximize hardware utilization and training throughput on our large-scale GPU clusters (thousands of NVIDIA Blackwell GPUs). You will work at the intersection of deep learning frameworks, distributed systems, and GPU microarchitecture, eliminating bottlenecks from the Python layer down to the GPU kernel. This role is for Aleph Alpha Research GmbH. Your responsibilities: * End-to-End Optimization: Profile training loops using PyTorch Profiler, Nsight Systems and Nsight Compute to identify system- and kernel-level bottlenecks in order to maximize model throughput. * Distributed Strategy and Topology: Configure and tune composite parallelism strategies (e.g. TP, DP, HSDP/FSDP, EP), optimizing load balance, minimizing critical-path bottlenecks, and managing communication-to-computation trade-offs for large-scale LLM training. * Hardware-Aware Modeling: Partner with AI Researchers to define model architectures for hardware efficiency without compromising convergence. YOUR PROFILE Basic Qualifications * Are proficient in Python and the PyTorch library. * Have a strong engineering background in parallel and/or distributed systems with proven track record of excellence. * Have hands-on experience with modern machine learning techniques (especially large language models and their life cycle). * Deeply understand the CUDA programming model. * Have experience in distributed programming with APIs like NCCL or MPI. * Have experience analysing profiling traces with tools such as PyTorch Profiler and Nvidia Nsight. * Please note this role requires regular on-site collaboration in Heidelberg as a member of the Training Efficiency Team. Preferred Qualifications * Contributions to modern distributed training frameworks (e.g., TorchTitan, Megatron-LM, DeepSpeed). * Familiarity with low-precision training formats (MXFP4, MXFP8) and their impact on numerical stability and throughput. * A deep understanding of NCCL communication primitives, NVSHMEM or CUDA IPC and their performance. * A proven track record of implementing and optimising modern transformer-based model training. * A proven track record working on the NVIDIA Blackwell architecture. COMPENSATION AND BENEFITS * Become part of an AI revolution! * 30 days of paid vacation * Access to a variety of fitness & wellness offerings via Wellhub * Mental health support through nilo.health * Substantially subsidized company pension plan for your future security * Subsidized Germany-wide transportation ticket * Budget for additional technical equipment * Flexible working hours for better work-life balance and hybrid working model * JobRad® Bike Lease

Aleph Alpha

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 Senior AI R&D Engineer in Model Training (f/m/d), you will join our model training team in Heidelberg or Berlin. Most of the team is based in Heidelberg. The model training team is training models, but more importantly in order to do so building and improving our model training pipeline. * You will 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 will 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 do not, and you will have real influence on what gets built and how. Your work directly shapes how quickly we can experiment and improve our models. * Identifying issues and taking initiative is what drives our day-to-day work. * Working mode, design decisions, priorities are all done in your team together with your team mates. The strongest teams often use highly collaborative techniques, like mob or pair programming. * Due to the highly collaborative nature of our work you are expected to be on-site at least two days a week. If you are in Berlin, you should expect to travel around every second month for a few days to Heidelberg. * We are specifically looking to strengthen the Software Engineering in the teams which are research heavy. Major points include improving the maintainability of our code through tests and design & architecture changes. REQUIREMENTS * At its core, you need to be able to dive into a codebase, change the behavior as necessary, and after the change the code should be better tested and easier to understand than before. * As such we look for candidates for an understanding of how to design for low coupling and high cohesion paired with the ability to incrementally refactor. * Experience with the following technologies is likely to be helpful: * Test Driven Development (TDD) * Trunk based development * Continuous integration * Domain Driven Design NICE-TO-HAVES * Most of our code is in Python, there is also the occasional Rust codebase. * Large parts of our training pipeline are built on top of Kubernetes. * We do not hire for skills in a particular technology or language, but rather ability to learn and mindset, yet experience with these technologies is a plus. WHAT WE OFFER * Become part of an AI revolution! * 30 days of paid vacation * Access to a variety of fitness & wellness offerings via Wellhub * Mental health support through nilo.health * Substantially subsidized company pension plan for your future security * Subsidized Germany-wide transportation ticket * Budget for additional technical equipment * Flexible working hours for better work-life balance and hybrid working model * JobRad® Bike Lease

Aleph Alpha

OUR MISSION Aleph Alpha is one of the few companies in Europe with end-to-end in-house model development including pre- and post-training. We’re building models that have general-purpose capabilities, but also specifically excel at addressing the needs of our customers. We're growing our post-training team in Heidelberg (or hybrid in Germany) and are looking for an AI Researcher who combines a deep theoretical understanding of reinforcement learning methods with a desire to improve on the state of the art and improve model capabilities in large-scale training. 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. ABOUT THE ROLE As a Senior AI Researcher for reinforcement learning you will shape and improve the underlying RL methodology, maintain a high-quality training code-base, and conduct large-scale experiments to hill-climb our performance benchmarks. This role is for you if you both have a strong theoretical background on RL and the engineering drive to bring these methods into production and improve on the methods as part of the reinforcement learning team. In your day-to-day you will conduct large-scale reinforcement learning experiments, derive hypotheses from the results, and iterate on both the implementation and methodology based on the observations. Together with a collaborative team, you will have direct impact on the models that we ship to our customers. This role is for Aleph Alpha Research GmbH. YOUR RESPONSIBILITIES * Hill-climb in large-scale training: Conduct large-scale LLM training runs, analyze evaluation scores in depth, propose hypotheses for improvement and directly implement them in order to maximize performance on our benchmarks. * Theoretical innovation: Stay at the bleeding edge of RL research. You will identify, implement, and iterate on novel approaches to multi-turn reinforcement learning. * Scale our training infrastructure: Identify bottlenecks in our training setup and optimize our RL training loops for large-scale training. * Cross-functional collaboration: Partner with our other post-training teams to turn raw feedback into actionable training signals, ensuring that our RL iterations lead to measurable improvements in downstream performance. YOUR PROFILE Basic Qualifications * A deep understanding of Reinforcement Learning theory and how it relates to modern RL methods. * Experience with multi-node LLM training (ideally using RL). You understand how to scale multi-node RL trainings and can reason about and implement distributed algorithms. * Familiarity with statistical methods for evaluation and experiment design. * Ability to reason about what an evaluation/environment measures and whether it matters - not just run benchmarks, but understand them. * Strong Python skills and comfort with ML tooling (especially torch distributed) * Willingness to relocate to Heidelberg or travel regularly (potentially weekly). Preferred Qualifications * PhD in reinforcement learning or equivalent research experience. * A history of contributions to top-tier venues (NeurIPS, ICML, ICLR, etc.) specifically regarding RL. * Experience evaluating LLM models and crafting environments for training. COMPENSATION AND BENEFITS * Become part of an AI revolution! * 30 days of paid vacation * Access to a variety of fitness & wellness offerings via Wellhub * Mental health support through nilo.health * Substantially subsidized company pension plan for your future security * Subsidized Germany-wide transportation ticket * Budget for additional technical equipment * Flexible working hours for better work-life balance and hybrid working model * JobRad® Bike Lease