Generate reusable Web Component custom element code with Shadow DOM, attributes, events, and slots
The Web Component Generator is a free online tool that helps developers create reusable custom HTML elements following W3C Web Components standards. Instead of writing boilerplate code from scratch, you can visually configure component properties, Shadow DOM, attributes, events, and slots, then generate production-ready code instantly. All processing happens locally in your browser — no data is uploaded to any server.
1. Enter your component name (must contain a hyphen, e.g., my-button).
2. Choose whether to extend a built-in HTML element or use the default HTMLElement.
3. Configure Shadow DOM, template, slots, and attribute observation options.
4. Add custom attributes with types and default values.
5. Write your CSS styles and HTML template, then click "Generate Code" or "Preview".
Create encapsulated, reusable UI components that work across any framework. Web Components are framework-agnostic and can be used with React, Vue, Angular, or vanilla JS.
Build distributable components that maintain their internal structure and styles regardless of the consuming application's CSS.
Understand Web Components concepts by generating and examining the code. The visual configuration makes it easy to see how each option affects the output.
Web Components are a set of browser-native APIs that allow creating reusable custom elements. The three pillars are Custom Elements (registering new HTML tags), Shadow DOM (encapsulated DOM and styling), and HTML Templates (inert DOM fragments). Unlike framework-specific components, Web Components work in all modern browsers and can be used with any framework or no framework at all. Major companies like GitHub, YouTube, and ING Bank use Web Components in production. The technology is supported by all modern browsers and is a W3C standard, ensuring long-term stability.
Web Components are a set of W3C standard technologies that allow developers to create reusable custom HTML elements. They consist of three core technologies: Custom Elements, Shadow DOM, and HTML Templates, enabling true encapsulation and reusability.
Shadow DOM is a DOM encapsulation technology that isolates a component's internal structure and styles from the rest of the page. CSS inside Shadow DOM doesn't affect outside elements, and external CSS doesn't leak in — achieving true style encapsulation.
Per the HTML specification, custom element names must contain at least one hyphen (-) to distinguish them from standard HTML elements. This prevents namespace conflicts. For example, my-button and custom-card are valid names.
Web Components support these lifecycle callbacks: connectedCallback (called when element is inserted into DOM), disconnectedCallback (called when removed from DOM), adoptedCallback (called when moved to a new document), and attributeChangedCallback (called when observed attributes change).
Absolutely safe! All code generation happens locally in your browser. No data is sent to any server, and no personal information is collected.