htmx is a lightweight JavaScript library that enables developers to perform AJAX requests, CSS transitions, WebSocket communication, and server‑sent events directly through HTML attributes, eliminating the need for extensive custom JavaScript. By extending standard HTML, it reduces code size and simplifies the workflow for building dynamic, server‑driven web applications while keeping the page structure declarative.
Funding
Funding not disclosed
Founders
Product
Problem
Web developers often need to add AJAX calls, CSS transitions, WebSocket communication, and server‑sent events to pages, which typically requires writing and maintaining separate JavaScript code or importing large client‑side frameworks. This adds complexity, increases bundle size, and makes it harder to keep the server‑rendered HTML as the single source of truth.
Solution
htmx is a lightweight, dependency‑free JavaScript library (under 20 KB gzipped) that enables these dynamic behaviors directly in HTML through custom attributes such as <code>hx-get</code>, <code>hx-post</code>, <code>hx-trigger</code>, and <code>hx-swap</code>. By allowing any element, event, or HTTP verb to initiate a request and update a specific DOM target, htmx lets developers build rich, interactive applications while keeping most logic on the server and serving HTML responses. The approach reduces client‑side code, eliminates the need for build pipelines or large frameworks, and preserves the original hypertext model of the web.
Target Audience
Primary users are front‑end developers and full‑stack teams building dynamic web applications who prefer server‑rendered HTML over heavyweight JavaScript frameworks.
Features
- Attribute‑driven AJAX support for all HTTP verbs (GET, POST, PUT, PATCH, DELETE) without writing JavaScript
- Event triggers and element targeting enable fine‑grained updates (e.g., replace, prepend, append) of specific DOM nodes
- Built‑in support for CSS transitions, WebSockets, and server‑sent events via simple HTML attributes
- Dependency‑free, under 20 KB gzipped, and usable via CDN, direct download, npm, or webpack import
- Works with any server‑side language; responses are standard HTML, keeping the server as the source of truth
- No build system required; integration is as simple as adding a single <script> tag to the page