Dialyzer is a static analysis tool used primarily for the Erlang programming language. It helps developers identify software bugs, type errors, and potential issues in their code without executing it. By analyzing the code's structure and flow, Dialyzer can provide insights that improve code quality and reliability. The tool operates on the principle of success typing, which means it focuses on the types of values that functions can accept and return. This allows Dialyzer to detect discrepancies and suggest improvements, making it a valuable resource for maintaining robust and efficient Erlang applications.