Applied AI Engineer

About Fundamental Fundamental is an AI research lab pioneering the future of enterprise decision-making. Our flagship model, NEXUS is the world's most powerful Large Tabular Model (LTM) - purpose-built for the structured records that contain trillions of dollars in business value. With $275m in funding from leading investors and trusted by Fortune 100 companies, Fundamental is giving businesses the Power to Predict. At Fundamental, you'll work on unprecedented technical challenges in foundation model development and build technology that transforms how the world's largest companies make decisions. This is your opportunity to be part of a category-defining company from the ground-up. Join the team defining the future of enterprise AI. Key responsibilities Take part in development and optimization of a large neural network-based tabular model implemented in Python Profile training and inference pipelines to identify performance bottlenecks Rewrite critical components in Rust (via PyO3 or custom extensions) where Python limits us, with C++ (via PyBind11 or custom extensions) as a secondary option where appropriate Improve memory efficiency, latency, and throughput across model pipelines Ensure correctness, numerical stability, and reproducibility as the model evolves Collaborate with ML researchers on productionizing new capabilities Maintain clean abstractions, comprehensive tests, and clear documentation Shape architectural decisions for our ML systems handling tabular data Must have Strong software engineering fundamentals with expert-level Python and Rust Hands-on experience bridging Python and Rust (PyO3, maturin, or custom extensions) Experience developing and maintaining ML models in production Strong understanding of neural networks Track record of optimizing performance-critical code Strong profiling and debugging skills (CPU, memory, latency) Nice to have Experience with tabular ML approaches (transformers, tree/NN hybrids, learned embeddings) Working proficiency in C++ and experience bridging Python and C++ (PyBind11, Cython, or custom extensions) Familiarity with PyTorch internals or writing custom ops (Rust or C++) Experience optimizing training loops, data pipelines, or inference engines Background in numerical computing or systems programming Exposure to large-scale ML infrastructure (distributed training, batching, caching) Experience with the Rust async ecosystem (tokio) or SIMD/parallelism crates (rayon, ndarray) Benefits Competitive compensation with salary and equity Comprehensive health coverage for you and your dependents Paid parental leave for all new parents, inclusive of adoptive and surrogate journeys Relocation support for employees moving to join the team in one of our office locations A mission-driven, low-ego culture that values diversity of thought, ownership, and bias toward action