htmx 4.x Complete Reference

htmx gives access to AJAX, CSS Transitions, WebSockets, and Server-Sent Events directly in HTML using attributes. No JavaScript needed for most interactive patterns.

htmx 4 uses fetch() (not XMLHttpRequest), has explicit attribute inheritance, swaps all HTTP responses by default, and includes a built-in morph algorithm.

Installation

<!-- CDN -->
<script src="https://cdn.jsdelivr.net/npm/htmx.org@next/dist/htmx.min.js"></script>

<!-- NPM -->
npm install htmx.org@next