TSLint is a static code analysis tool used to identify and fix problems in TypeScript code. It helps developers maintain code quality by enforcing coding standards and best practices. By analyzing the code for potential errors, it can catch issues early in the development process, making it easier to maintain and understand. Although TSLint was widely used, it has been deprecated in favor of ESLint, which now supports TypeScript through plugins. Developers are encouraged to transition to ESLint for improved functionality and ongoing support in the JavaScript and TypeScript ecosystems.