Web Components are a set of standardized technologies that allow you to create reusable, encapsulated elements for the web. These technologies are designed to work natively in browsers, enabling you to build custom elements that integrate seamlessly with existing HTML, CSS, and JavaScript. The main standards that make up Web Components are custom elements, shadow DOM, and HTML templates.

Custom elements let you define your own HTML tags by registering a class that extends the standard HTMLElement. This makes it possible to create new, meaningful elements with their own behavior and lifecycle, just like built-in elements such as <button> or <input>.

The shadow DOM provides a way to encapsulate a component's internal structure and styles. When you use shadow DOM, the styles and markup inside your component are isolated from the rest of the page. This means that CSS defined inside a component does not leak out, and styles from the outside do not affect the component's internals. This encapsulation is a key benefit of Web Components, as it prevents style conflicts and makes components more predictable.

HTML templates allow you to define chunks of markup that are not rendered by default. Instead, you can clone and reuse these templates within your components as needed. Templates are especially useful when you need to create multiple instances of the same structure dynamically.

Together, these standards provide encapsulation—hiding implementation details and preventing unwanted interference from the outside—and interoperability, meaning your components can be used anywhere HTML is used, regardless of framework or library. This makes Web Components a powerful tool for building modern, maintainable, and reusable user interfaces.