This paper presents a comprehensive atomic and molecular database for analyzing submillimeter line observations. The database includes energy levels, statistical weights, Einstein $A$-coefficients, and collisional rate coefficients for a variety of astrophysically important species. These data are essential for non-LTE line radiative transfer simulations and are made publicly available through a WWW interface. An online version of the RADEX computer program, which performs statistical equilibrium calculations, is also provided. The paper discusses the methods used to extrapolate collisional rate coefficients to higher energies and temperatures, and compares calculated emission lines using different sets of collisional rate coefficients. The database is intended to be a valuable tool for analyzing observations from current and future submillimeter and infrared telescopes.This paper presents a comprehensive atomic and molecular database for analyzing submillimeter line observations. The database includes energy levels, statistical weights, Einstein $A$-coefficients, and collisional rate coefficients for a variety of astrophysically important species. These data are essential for non-LTE line radiative transfer simulations and are made publicly available through a WWW interface. An online version of the RADEX computer program, which performs statistical equilibrium calculations, is also provided. The paper discusses the methods used to extrapolate collisional rate coefficients to higher energies and temperatures, and compares calculated emission lines using different sets of collisional rate coefficients. The database is intended to be a valuable tool for analyzing observations from current and future submillimeter and infrared telescopes.