RSPt is a code for electronic structure calculations and its acronym stands for Relativistic Spin Polarized toolkit. RSPt offers a robust and flexible set of tools to calculate the band structure and total energy for all elements, and combinations thereof, over a wide range of volumes and structures. RSPt is based on the Full-Potential Linear Muffin-Tin Orbital (FP-LMTO) method, which allows for very small basis sets and fast calculations, without any restriction on the symmetry of the potential. RSPt accommodates multiple energy sets (i.e. valence and semi-core states) with the same angular quantum numbers but different principal quantum number, which is ideal to provide an accurate description of semi-core states. The code can be used for spin-polarized and/or spin-orbit calculations with several LDA and GGA functionals implemented, as well as up-to-date implementations of beyond DFT methods, such as SIC, DFT+U or DFT+DMFT. No material library is needed as all input data is created on the fly.