Tabler is a free and open-source HTML dashboard UI kit built on Bootstrap 5, providing a set of ready-made layouts, components, and demo pages for admin panels, dashboards, and web apps. It includes over 120 demo pages, a dark color scheme, and RTL support. The kit is customizable with Sass or CSS custom properties and comes with a range of plugins. Tabler is designed to work with any framework and has a simple setup guide for popular frameworks like React, Vue, and Angular.