Interfaces in TypeScript are a fundamental feature that define the structure or shape of an object, specifying the properties and methods it should have, primarily for the purpose of type-checking. They offer several benefits, including highlighting type errors to reduce runtime issues, defining clear contracts for functions and code, and enhancing documentation and readability. Interfaces promote code reusability and consistency by allowing extensions and reuse across various parts of an application. They also facilitate easier refactoring, as changes adhering to the same interface do not impact dependent code. Interfaces can be used to type functions, define optional and readonly properties, and implement class structures, while also supporting advanced features like index signatures, extending interfaces, discriminating unions, and generic interfaces. By integrating with IDEs, interfaces enhance developer productivity through autocompletion and improved code navigation, making them an essential tool for efficient and reliable TypeScript development.