Polyfills
The webcomponent.js polyfills enable Web Components in (evergreen) browsers that lack native support.
Install with Bower bower install webcomponentsjs
Install with npm npm install webcomponents.js
Download webcomponents.js 0.7.12 (117KB minified, 34KB gzipped)
Browser Support
| Chrome | Opera | Firefox | Safari | IE/Edge | |
Libraries

Polymer
Polymer is a new type of library for the web, built on top of Web Components, and designed to leverage the evolving web platform on modern browsers.

X-Tag
X-Tag is a small JavaScript library, created and supported by Mozilla, that brings Web Components Custom Element capabilities to all modern browsers.

Bosonic
Bosonic is a set of tools that enable you to build Web Components as the spec currently describes, and supporting not-so-modern browsers like IE9.
Discover
Specs

Custom Elements
This specification describes the method for enabling the author to define and use new types of DOM elements in a document.

HTML Imports
HTML Imports are a way to include and reuse HTML documents in other HTML documents.

Templates
This specification describes a method for declaring inert DOM subtrees in HTML and manipulating them to instantiate document fragments with identical contents.

Shadow DOM
This specification describes a method of establishing and maintaining functional boundaries between DOM trees and how these trees interact with each other within a document, thus enabling better functional encapsulation within the DOM.
Articles
Sane usage of Custom ElementsWeb Components have been an controversial subject that surfaced the Front end world over the last years that I'm still pretty skeptical about its usage on existing and greenfield projects due the lack of good examples on how they can be rolled out to production, but there is sure a way to get started with them without buying in all the hype.
Read More >Presentations
Polymer SummitThe first ever Polymer Summit in Amsterdam. Tune in as the Polymer Team shares best practices and exciting announcements, and talks about the past, present, and future of the framework.
Read More >