  Spectral energy distribution (SED) models of galaxies at $0.3\leq z \leq 2.5$
were constructed to be processed by the Euclid spectroscopic channel simulator
in order to investigate the \Euclid Near-Infrared Spectrometer and Photometer
(NISP) capabilities. We developed a solid methodology to build a realistic and
representative synthetic SED library of star-forming galaxies, including
reliable emission line fluxes and widths. The construction of the SEDs consists
in computing the continuum using the Bruzual \& Charlot (2003) models, calling
out SED fitting parameters available in publicly released multi-wavelength
catalogues. Emission lines were added using empirical and theoretical
relations.
