The ddX library represents the culmination of over ten years of dedicated effort in the field of polarizable continuum solvation models (PCSM). With the library, we provide three PCSMs based on the domain decomposition paradigm, namely ddCOSMO, ddPCM, and ddLPB, under a single easy-to-use API available via multiple programming languages. Notably, the implemented methods are robust and exhibit a linear scaling regime in both time and memory. Being interfaced to multiple host codes ddX is already able to tackle solvation effects in molecular systems ranging from molecules to proteins, thus bridging for the first time the application regimes of quantum chemistry and biophysics.