The title compound, C₁₃H₁₅N₃O₇, crystallizes as two independent molecules which differ in their conformation. Intermolecular hydrogen bonding between the amide and carboxylic acid groups as N-H...O=C interactions results in the formation of one-dimensional chains with N...O distances of 2.967 (6) and 3.019 (6) Å. Neighbouring chains are linked by C=O...H-O interactions to form a two-dimensional network, with O...O distances of 2.675 (6) and 2.778 (6) Å.