Spinsymm is an open-source library for generating and analyzing spin Hamiltonians based on spatial symmetries. It can be used to construct spin Hamiltonians satisfying all spatial symmetries of the considered physical system consisting of many different interaction terms, including Heisenberg exchange, Dzyaloshinsky-Moriya interaction, magnetocrystalline anisotropy and multispin interaction terms. The library can provide spin configurations for first-principles simulations, and determine the values of the interaction parameters based on the total energies of these configurations obtained from these simulations.