A .tsx file is a TypeScript file that includes JSX syntax. TypeScript is a superset of JavaScript that adds static typing to the language. JSX is a syntax extension to JavaScript that allows you to write HTML-like code within your JavaScript/TypeScript files. This combination is commonly used in React development, where JSX is used to define the structure and content of UI components, and TypeScript provides type safety and improved code maintainability. The .tsx file is typically compiled into a standard .js file by a TypeScript compiler (like tsc) or a build tool (like Webpack or Parcel) before being executed in a web browser or other JavaScript runtime environment. The compiler transforms the JSX syntax into standard JavaScript function calls that create the corresponding DOM elements. Using .tsx files allows developers to leverage the benefits of both TypeScript and JSX, resulting in more robust, maintainable, and readable code for building user interfaces.