In the cation of the title salt, C₁₀H₁₀N₃⁺·C₆H₂N₃O₇⁻, the pyridine and pyridinium rings are linked by an intramolecular N—H...N hydrogen bond and are approximately coplanar, with a dihedral angle between their planes of 4.24 (6)°. In the crystal, the cations and anions are linked through N—H...O hydrogen bonds, forming supramolecular chains propagating along thec-axis direction. π–π stacking is observed between neighbouring chains, the centroid–centroid distances being 3.7638 (11) (between pyridinium rings) and 3.5331 (11) Å (between benzene rings).