Interpreting and understanding complex, organ-level mass cytometry datasets represents a formidable interdisciplinary challenge. This study aims to identify, describe, and interpret potential developmental trajectories of thymocytes and mature T cells. We developedtviblindi, a trajectory inference algorithm that integrates several autonomous modules - pseudotime inference, random walk simulations, real-time topological classification using persistence homology, and autoencoder-based 2D visualization using thevaevictisalgorithm. This integration facilitates an interactive exploration of developmental trajectories. The utility and proficiency oftviblindiare demonstrated through comprehensive analysis of the thymic and peripheral T-cell compartment. Our approach not only uncovers and elucidates the canonical CD4 and CD8 development but also offers insights into various checkpoints such as TCRβ selection and positive/negative selection, elucidating the crossroads between further development and apoptosis. Finally, we identify and thoroughly characterize thymic regulatory T cells, tracing their development from the negative selection stage to mature thymic regulatory T cells with an extensive proliferation history and an immunophenotype of activated and recirculating cells.tviblindiis a versatile and generic approach suitable for any single-cell dataset, equipping biologists with an effective tool for interpreting complex data.