Delgado-Friedrichs and O'Keeffe explained the overall architecture of the Systre algorithm which CrystalNets.jl largely reuses: we will follow its structure, only briefly summarising the key concepts that are already explained elsewhere along the way, while focusing on the implementation choices and some proofs of correctness that do not appear in other publications. We will then focus on a series of new optimisations of the algorithm that allow to greatly improve its performance for most nets. Finally, we will demonstrate the applicability of the method by analysing several existing crystalline databases using CrystalNets.jl.