In the title compound, C7H13NO4, there are two independent mol­ecules in the asymmetric unit. All bond lengths and angles in the mol­ecules are in normal ranges. The ψ1 and ψ2 torsion angles are 159.9 (4) and −23.4 (5)°, respectively, in the first molecule, and the ψ3 and ψ4 torsion angles 157.7 (4) and −26.7 (5)°, respectively, in the second. Each of the independent mol­ecules has a different comformation. The translationally and screw‐related mol­ecules are connected by N—H⋯O hydrogen bonds, forming a two‐dimensional network parallel to the ac plane.