SFQEDtoolkit implements strong-field QED (SFQED) processes in existing particle-in-cell (PIC) and Monte Carlo codes to determine the dynamics of particles and plasmas in extreme electromagnetic fields, such as those present in the vicinity of compact astrophysical objects. The code uses advanced function approximation techniques to calculate high-energy photon emission and electron-positron pair creation probability rates and energy distributions within the locally-constant-field approximation (LCFA) as well as with more advanced models.