The debugging activity is carried out following the flow of the running program (tracing). In each line of code, the coder displays the operations performed by the instructions in real time and the values recorded in the variables. In this way, the developer can check that everything is working properly or identify the cause of a malfunction.

Each programming language has its own debugger. However, there is no valid debugger for all programming languages because each language has its own syntax and grammar. The debugger executes the step-by-step source code. Therefore, the debugger must know the rules of the language, like the compiler.