Grid computing allows the utilization of vast computational resources for solving complex scientific and engineering problems. However, development tools for Grid applications are not as mature as their traditional counterparts, especially in the area of debugging and testing. Debugging Grid applications typically requires a programmer to address non-trivial issues such as heterogeneity, job scheduling, hierarchical resources, and security. This paper presents the design and implementation of a Grid service debug architecture that is compliant with the Web Service Resource Framework standard. The debugger provides a library with a set of welldefined debug APIs.