We introduce the pCI software package for high-precision atomic structure calculations. The standard method of
calculation is based on the configuration interaction (CI) method to describe valence correlations, but can be extended
to attain better accuracy by including core correlations via many-body perturbation theory (CI+MBPT) or the all-order
(CI+all-order) method, as well as QED corrections via QEDMOD. The software package enables calculations of atomic
properties, including energy levels, g-factors, hyperfine structure constants, multipole transition matrix elements, polariz-
abilities, and isotope shifts. It also features modern high-performance computing paradigms, including dynamic memory
allocations and large-scale parallelization via the message-passing interface, to optimize and accelerate computations.