This article discusses the evaluation of the usability of wireframe designs using Nielsen & Molich heuristic approach. It covers the efficiency of the interface design and its different criteria such as visibility of system status, match between system and the real world, user control and freedom, consistency and standards, error prevention, recognition rather than recall, flexibility and efficiency of use, aesthetic and minimalist design, help users recognize, diagnose, and recover from errors, and help and documentation. The article also includes a bibliography for further reading.