Bioimage frameworks based on artificial intelligence (AI) offer powerful tools for image segmentation, but their technical overhead often creates a gap between developers and the broader bioimaging community. Biom3d addresses this challenge by providing a modular, PyTorch-based architecture designed to enable reproducible and interoperable 2D and 3D segmentation pipelines while maintaining strict adherence to FAIR principles. The framework’s engineering quality is demonstrated through low intra-module complexity, high modularity, and seamless interoperability, exemplified by the successful substitution of transformer-based MONAI models. Its architecture is organized around seven core module types, allowing fine-grained control over data handling, model configuration, optimization, and evaluation. Its default configuration, nnCore, autoconfigures optimal pipelines based on new datasets and competes with state-of-the-art 3D segmentation methods, outperforming classical tools such as NucleusJ/NODeJ and matching the robustness of nnU-Net across diverse modalities. Biom3d is accessible through multiple interfaces including a graphical user interface, a Jupyter Notebook, a command-line tool, a Docker image and as a Python library. Biom3d is compatible with OMERO (Open Microscopy Environment Remote Objects) for streamlined data management and reproducible computation, including execution on HPC servers. Collectively, these results position Biom3d as a sustainable and extensible framework for building, sharing, and reusing advanced bioimage analysis solutions.