The title compound, C(10)H(13)N(3)O(2)S, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In the crystal, the A and B mol-ecules are linked via pairs of N-H⋯O and O-H⋯S hydrogen bonds, forming dimers with R(2) (2)(14) and R(2) (2)(6) ring motifs. These dimers are linked via a pair of N-H⋯S hydrogen bonds with an R(2) (2)(8) ring motif, forming chains propagating along the c-axis direction. The crystal was refined as an inversion twin with a final BASF ratio of 0.54 (11):0.46 (11).