Polymer is a library that uses the latest web technologies to let you create custom HTML elements. Build anything from a button to a complete application as an encapsulated, reusable element that works across desktop and mobile.

Ligi is described as 'Js is a Javascript micro-library for keeping DOM elements in sync with arrays, and updating only properties that have changed. It is not a full declarative framework, but a simple set of utilities to help with reactivity in pure Javascript' and is an app in the development category. There are more than 10 alternatives to Ligi for a variety of platforms, including Self-Hosted, JavaScript, Windows, Linux and Web-based apps. The best Ligi alternative is Vue.js, which is both free and Open Source. Other great apps like Ligi are React, Angular, Svelte and Vite.
Polymer is a library that uses the latest web technologies to let you create custom HTML elements. Build anything from a button to a complete application as an encapsulated, reusable element that works across desktop and mobile.

A toolchain for building reusable, scalable Design Systems. Generate small, blazing fast, and 100% standards based Web Components that run in every browser.
With more than 80 UI components, including advanced tables, charts, and forms, this open-source JavaScript framework will help you build complex, data-rich web applications faster and more efficiently.