The paper introduces PLUTO, a numerical code designed for solving hypersonic flows in one, two, and three spatial dimensions using a modular and multi-physics approach. The code is particularly suited for astrophysical flows involving discontinuities and can handle Newtonian, relativistic, MHD, and relativistic MHD fluids. PLUTO employs modern Godunov-type shock-capturing schemes and is validated against various benchmarks. The code is structured to allow for easy incorporation of new modules and supports both single-processor and parallel computing. The paper details the code's design, including its modular structure, numerical methods, and physics modules for hydrodynamics, magnetohydrodynamics, relativistic hydrodynamics, and relativistic magnetohydrodynamics. It also discusses the treatment of source terms and non-hyperbolic terms, such as geometrical source terms and optically thin cooling. The code's performance is demonstrated through tests on double Mach reflection and under-expanded jet problems, showing its accuracy and efficiency in simulating complex astrophysical phenomena.The paper introduces PLUTO, a numerical code designed for solving hypersonic flows in one, two, and three spatial dimensions using a modular and multi-physics approach. The code is particularly suited for astrophysical flows involving discontinuities and can handle Newtonian, relativistic, MHD, and relativistic MHD fluids. PLUTO employs modern Godunov-type shock-capturing schemes and is validated against various benchmarks. The code is structured to allow for easy incorporation of new modules and supports both single-processor and parallel computing. The paper details the code's design, including its modular structure, numerical methods, and physics modules for hydrodynamics, magnetohydrodynamics, relativistic hydrodynamics, and relativistic magnetohydrodynamics. It also discusses the treatment of source terms and non-hyperbolic terms, such as geometrical source terms and optically thin cooling. The code's performance is demonstrated through tests on double Mach reflection and under-expanded jet problems, showing its accuracy and efficiency in simulating complex astrophysical phenomena.