3,4-Di-amino-pyridinium hydrogen malonate.

In the title salt, C5H8N3+·C3H3O4−, the 3,4-di­amino­pyridinium cation is almost planar, with an r.m.s. deviation of 0.02 A. The conformation of the hydrogen malonate anion is stabilized by an intra­molecular O—H⋯O hydrogen bond, which generates an S(6) ring. In the crystal, N—H⋯O hydrogen bonds link cations and anions into layers parallel to the ab plane.