Unpoly

Unpoly enhances server-rendered HTML so links and forms update page fragments instead of full pages, without building a SPA. The server still renders HTML — Unpoly handles the smart patching, caching, overlays, and lifecycle.

Current version: 3.12 — API reference | Changelog

Core mental model

1. Fragments — CSS-selector-targeted pieces of a page that get swapped on navigation
2. Layers — A stack of contexts (root + any number of overlays)
3. Compilers — JS functions that run whenever matching elements are inserted into the DOM
4. Navigation — Link/form interactions that change history and trigger fragment updates

Quick reference: key HTML attributes