HTMX is a JavaScript library that allows you to access AJAX functionality directly in HTML, using attributes, so you can progressively enhance your website's user experience. It enables developers to create dynamic web pages without writing a lot of JavaScript code or dealing with complex client-server interactions. HTMX works by adding attributes to HTML elements that trigger AJAX requests when certain events occur, such as clicking a link, submitting a form, or changing the value of an input field. It then updates the DOM with the response from the server, allowing for seamless user interactions and fast page loads. HTMX is lightweight, easy to use, and compatible with existing web frameworks and libraries. It is used by developers to enhance the interactivity and responsiveness of their web applications while maintaining a clean and maintainable codebase.