How many photo carousels have you built? Date pickers? Dynamic tables and charts? Wouldn't it be great if there was a way to make these custom elements encapsulated and reusable? Welcome to Web Components! The building blocks are well known: HTML templates, custom elements, HTML imports, and shadow DOM. It's fairly easy to build simple examples. But what happens when performance degrades? Join this discussion of the synchronous and asynchronous nature of web components, and how they can impact the rendering of the entire page.