Sindarin is a versatile and interactive debugger scripting API for object-oriented programming languages. Sindarin is designed to help building dedicated debugging tools targeting specific problems or domains. To do this, Sindarin attaches to a running process then exposes stepping and introspection operations to control, manipulate and observe that process’ execution. It simplifies the creation of personalized debugging scripts by providing an AST-based API, thus also proposing different stepping granularity over the debugging session. Once written, scripts are extensible and reusable on other scenario, and can be used to build more complex debugging tools.