Drupal developers always face the dilemma of building classic multi-page applications or headless solutions with a modern JavaScript stack. Especially when they need to build UIs that feel fast and are highly reactive. While there were some Drupal specific solutions for parts of this need (Form State API, AJAX API and BigPipe), these were dated, only solving very specific use cases and comparatively heavy in implementation.
HTMX is a tiny, dependency-free, and extensible JavaScript library that allows you to access modern browser features directly from HTML, rather than using extensive amounts of JavaScript. It essentially enables you to use HTML to make AJAX requests, CSS transitions, WebSockets, and Server-Sent Events (SSE) directly.
As a replacement for Drupal's mostly home grown solutions, this reduced the loaded JavaScript size by up to 71% for browser-server interactions, including HTML streaming with BigPipe. While enabling a whole set of new functionality at the same time!
