POpSiCLE stands for PhOtoelectron SpeCtrum library for Laser-matter intEractions, and it is a library that allows the calculation of photoelectron spectra for various grid-based solutions of the time-dependent Schroedinger equation (and time-dependent Kohn Sham equations of TDDFT). Methods implemented include Fourier transform methods, Hankel transforms, the surface flux method (tSURFF) and the sampling point method. It works from a variety of highly-parallelised codes.