Recent experiments have highlighted the efficiency of nonprecious metal-based hybrid structures, such as g-C₃N₄/MoS₂ and g-C₃N₄/graphene for hydrogen evolution reaction (HER). This work focuses on the interface effects of such hybrid heterostructures that could lead to the enhanced catalytic activity of g-C₃N₄. We have concentrated on the hybrid electrocatalysts with the architecture g-C₃N₄/X (X = WTe₂, MoS₂, and graphene), where the interface plays an important role in the overall HER. These promising candidates have been assessed using three main factors extracted from density functional theory calculations, namely: (i) the free energy of hydrogen adsorption on the catalytic site ΔG_H, (ii) Schottky barrier potentials, and (iii) induced charge polarization across the interface. We have found that particularly g-C₃N₄/WTe₂ displays a suitable combination of the investigated properties standing out as a potential electrocatalyst for efficient hydrogen evolution reaction. Furthermore, the electronic structure fingerprints controlling the HER thermodynamics have been investigated. In particular, the N–H bonds have been found to display strong s–p hybridization and, additionally, ΔG_H decreases as the center of N p-band approaches the Fermi energy. This is also a relevant result in understanding HER mechanisms of organic compounds.