Software SPD_CLIENT provides a library and several executables for implementing interface to slant path delay, atmosphere opacity and antenna temperature on client side and a client routines for computing path delay path for satellite or air-borne altimetry by interacting with the SPD server. 1) Two are public routines are required for computing path delay using the time series of slant path delay expanded over azimuth and elevation for a set of stations: SPD_LOAD_BSPD -- load the data from a directory with expansion coefficients in bspd format SPD_INTRP_DELAY -- compute path delay by interpolation Executable spd_3d_toser transforms the expansion coefficients from ascii SPD format to binary BSPD format. Two example programs are provided: spd_show -- example of computing path delay at a given epoch. sob_show -- example of computing opacity and atmosphere brightness temperature at a given epoch. 2) Three public routines that are required for computing path delay for altimetry: spd_cli_init -- parsing control file, initialization, and checking whether the SPD server is running. spd_cli_get_2pd -- sending request to compute path delay to the SPD server, waiting for the response, parsing the results. spd_cli_quit -- deallocation of dynamic memory. These three routines can be called from Fortran, C, or MATLAB. Three examples are provided: spd_cli_example_fortran.f spd_cli_example_c.c spd_cli_example_fortran.f 3) Three public routines that are required for computing path spd_res_intrp -- get_spd_res -- get_spd_res_azel -- 4) Include files: spd.i spd_local.i spc.h